gray circle

Glossary of Medical Terms

We hear medical jargon everywhere, especially on television and in movies and some of it has even crept into everyday conversations and vocabulary.

But do you really know what these words and terms mean? We’ve assembled a glossary of various medical terms, acronyms, root words, prefixes and suffixes with links to insightful blogs to deepen your understanding and knowledge of various medical specialties. We will continue to update this glossary and hope you find it helpful in your journey to become a physician.

  • Medical terms: Words that are frequently used among practitioners.
  • Medical prefixes: Letters added to the beginning of a medical word to modify the meaning.
  • Medical suffixes: Letters added to the end of a medical word to change its meaning.
  • Medical root words: The base part of a medical word that conveys meaning.
  • Medical abbreviations and acronyms: Shorthand versions of common health care terms.


At AUC, our goal is to help you achieve your dreams of becoming an MD. Learn More


-, an- (prefix)

Lack of or without.

a.c. (acronym)

From the Latin “ante cibum,” meaning “before meals.” Related to the timing of administering medication.


A minor cut or scrape. 


A fluid-filled pocket that forms in tissue, usually due to bacterial infection.

ADR (acronym)

Adverse Drug Reaction.

ALCAPA (acronym)

Anomalous left coronary artery from the pulmonary artery

Related article:

A Heart-to-Heart Chat with Pediatric Cardiologist Anne A. Tedga, MD '11

ALOC (acronym)

Acute Loss of Consciousness.

ALS (acronym)

Advanced life support.

ANED (acronym)

Alive No Evidence of Disease.

angle-closure glaucoma

antithyroid drugs

ARDS (acronym)

Acute Respiratory Distress Syndrome. Occurs when a patient’s lungs fill with fluid, depriving the body of oxygen.

Related Articles:

ARF (acronym)

Acute Renal Failure. A sudden and dangerous condition in which the kidneys are unable to filter waste from the blood.


ASA (acronym)

Acetylsalicylic Acid, commonly known as aspirin.

-ation (suffix)

Indicates a process.

autoimmune thyroiditis



BDS (abbreviation)

From the Latin “bis die sumendum,” meaning “two times per day.” Typically in reference to when medication should be administered.


Not cancerous.

Beta-amyloid plaque burden


A small sample of tissue excised from a patient for testing. 

bl wk (abbreviation)

Blood work.

blood culture

A test used to find any unusual bacteria or fungi in a patient’s blood.

blood gas

A test to measure oxygen, carbon dioxide, and the pH of a patient’s blood.

blood pressure

The measure of how well the blood is circulating.

BLS (acronym)

Basic Life Support. The care given to a patient experiencing cardiac arrest, respiratory distress, or an obstructed airway.

BP (acronym)

Blood Pressure.


cardi/o- (prefix)

Related to the heart


Cardiologists treat a range of conditions. The most critical include heart attack and heart failure, in which the heart fails to pump sufficient blood around the body. Cardiologists may also treat arrhythmias (problems with heart rhythm) and congenital (inborn) heart conditions. They may aid patients with atherosclerosis, sometimes called hardening of the arteries, or hypertension (high blood pressure).

Related Articles:

cardiothoracic surgeon

A cardiothoracic surgeon performs surgery on your heart, lungs or esophagus and other parts of your chest. Surgeries can range from a heart valve replacement or heart transplant to treating lung cancer or esophageal cancer. Cardiothoracic surgeons have extensive training and can specialize in heart surgeries or other areas. 

Related Articles:

CAT scan (acronym)

Computerized Axial Tomography. A form of diagnostic imaging. 

celiac disease

central line

A catheter placed in a large vein that allows multiple IV fluids to be administered and blood to be drawn more easily.

Cholinesterase inhibitors (donepezil, galantamine, rivastigmine)


Signifies a recurring, persistent condition like heart disease.

Chronic traumatic encephalopathy (i.e. punch drunk syndrome)

clinical rotations

Clinical rotations in medical school are assigned shifts at an approved healthcare site. Once assigned to a site, students deliver supervised care individually and as a team. Tasks such as patient interviews, examinations, lab data reviews, and team discussions are common practice.

Each clerkship lasts several weeks at one site before students rotate to another. Therefore, students have a unique opportunity to take a deep dive into each rotation’s discipline. At the end of the rotation, clinical instructors evaluate performance. Students must also successfully pass standardized tests—called shelf exams—to advance.

Generally, students complete 80 weeks of clinical rotations in medical school. There are two types of clinical rotations: core and elective. Although specific core rotations are required, students may request different elective rotations.

Core clinical rotations generally include the following disciplines:

  • Internal Medicine, which aims to prevent, diagnose, and treat internal diseases in adults.
  • Family Medicine focuses on patients of all ages and covers pediatrics, adults, and the elderly.
  • Surgery involves operations that treat disease or minor injury to severe trauma.
  • Psychiatry focuses on diagnosing, treating, and preventing mental, emotional, and behavioral disorders.
  • Obstetrics and Gynecology include women’s health and wellness, prenatal/postpartum care, labor, and delivery.
  • Elective rotations give students a chance to focus on their specialty of choice.

Related Articles:


An area of injured tissue; bruise.

CPR (acronym)

Cardiopulmonary Resuscitation; also called mouth-to-mouth resuscitation. CPR is used during a medical emergency to keep oxygenated blood flowing to the brain and other vital organs through chest compressions and artificial ventilation.

C-spine (abbreviation)

Cervical spine.

CTE (acronym)

chronic traumatic encephalopathy (i.e. punch drunk syndrome)




A medical device that uses electric shocks to restore normal heartbeat.

derm/a/o, dermat/o (prefix)

Pertaining to the skin.


A dermatologist is a doctor specially trained in finding, preventing, and treating diseases of the skin, hair, nails, and adjacent mucous membranes.

As a dermatologist, you will be able to identify and treat more than 3,000 conditions, and you can help improve the quality of life for people suffering from minor and irritating conditions to severe and life-threatening maladies.

They are the front line of defense against the most common type of cancer—skin cancer. According to the American Cancer Society, more than 100,000 people in the United States are diagnosed with melanoma—a deadly but highly treatable skin cancer—each year.

Related Articles:

diabetes insipidus


A procedure to filter blood for patients with kidney failure. 

DNR (acronym)

Do Not Resuscitate; a medical order indicating that providers should not perform life-saving measures on a patient.

DOA (acronym)

Dead on Arrival.

Doctor of Osteopathy (DO)

Osteopathic schools also teach these treatments, but they add extensive training in hands-on diagnosis and treatment. Osteopathic medicine aims to heal the whole body—rather than a specific part—to fight a disease, and DO’s may prioritize physical therapy or manipulation over the use of medication or invasive procedures. Osteopathic methods are considered holistic—even “alternative.”

Osteopathic medicine involves all aspects of traditional medicine and includes various medical specialties. But osteopathic medicine expands on traditional medicine, adding that the musculoskeletal system is key to the successful operation of all other body systems. DO’s use osteopathic manipulative treatment (OMT) of the musculoskeletal system as a diagnostic and treatment tool. (OMT is also called osteopathic manipulative medicine, or OMM.) A hands-on technique, OMT may include pressure, resistance, or stretching to move a patient’s bones, joints, muscles, and tissues. OMT is used to treat such ailments as arthritis, headaches, sports injuries, stress injuries, and pain in the lower back, neck, shoulders, or knees. OMT may also treat hypertension and cardiac, kidney, and respiratory ailments—even COVID-19. Some key tenets of osteopathy are:

  • The body is a unit, and a person is a combination of body, mind, and spirit
  • The body is capable of self-healing, self-maintenance, and self-regulation
  • Structure and function are reciprocally interrelated

Related Article:

dys- (prefix)

Abnormal, difficult, or painful.


severe pain during periods, cramps lasting longer than 3 days; sometimes accompanied by nausea, fatigue and diarrhea

Related article:

Endometriosis vs PCOS: Differences and Similarities Explained



ears nose throat (ENT) / otolaryngologists

ENTs treat conditions in the ears, nose, and throat as well as the head and neck. Let’s take a closer look at what an ENT does in each area.

  • Ears: ENTs treat conditions affecting hearing, tinnitus, ear infections, balance, nerve pain, and facial and cranial nerves. Some treatments are primarily pharmaceutical, but ENTs may also perform surgeries on the ear.
  • Nose: ENTs are on the front lines against nasal allergies and chronic sinusitis. They also perform surgery, such as to repair a deviated septum in the nose.
  • Throat: For the throat, ENTs may aid patients with problems such as swallowing or speech. They may also treat conditions involving the esophagus.
  • Head and Neck: ENTs also treat a variety of conditions in the head and neck area, such as tumors or deformities. In these cases, ENT doctors may perform reconstructive and plastic surgery. Importantly, in addition to surgical treatment of tumors, ENTs also treat thyroid disorders, enlarged thyroid glands, parathyroid disease, and more.

Related Article:

-ectomy (suffix)

Surgical removal of something.

ED/ER (acronym)

Emergency Department or Emergency Room.


Swelling caused by fluid accumulation.

EEG (acronym)

Electroencephalogram. A diagnostic tool that measures electrical activity in the brain.

EKG (acronym)

Electrocardiogram, a way of monitoring the heart and testing for problems.

EKG/ECG (acronym)

Electrocardiogram. A test that records the electrical signals in the heart.


An arterial blockage, often caused by a blood clot.

EMS (acronym)

Emergency Medical Services.

encephal/o (prefix)

Related to the brain.


The outer layer of the skin.




Fellowships offer a pathway for physicians to hone their skills in a subspecialty through structured training and research, and the options continue to expand. 

Related Articles:

forensic pathology/forensic pathologist

Forensic pathology is a subspecialty of pathology that examines cases of sudden, suspicious, or violent death. Forensic pathologists study the dead to determine why and how they died. They may be called to present their findings in court.

Related Articles:


Broken bone or cartilage.

frontotemporal degeneration



gastr/o (prefix)

Related to the stomach.

general anesthesia

General anesthesia involves rendering the patient completely unconscious for the duration of surgery. Putting the patient under always carries some medical risk, so general anesthesia is often reserved for the most major surgical procedures, including open-heart surgery and major joint replacement. 

general surgeon

Whereas surgical specialists focus on a particular organ or region of the body, general surgeons are experts in common surgeries such as splenectomies (spleen removal) and appendectomies (removal of the appendix). Their broad training and surgical knowledge gives them an advantage when dealing with issues affecting multiple organs and systems of the body.

Related Article:


An organ or tissue that produces and secretes fluids that serve a specific function.

gynecologic oncology

Gynecologic oncology focuses on the study and treatment of malignancies arising in the female reproductive tract.

 Related Article:


Related articles:

Specialty Webinar: All About Obstetrics and Gynecology

OB-GYN Meaning: What is Obstetrics and Gynecology?

A Chat with Ingrid Paredes, AUC MD '11

Chyrisha Rucker, Class of '25, Strives to change the narrative for Black women in medicine

Types of Surgery: What Field of Medicine is Right for You?

Addressing Sexual Health with Richard Bloy, MD, FACOG

Internal Medicine vs Family Medicine: What's the Difference?

How Cultural Competence Improves Hispanic Maternal Health

Match Day 2023: Canadian student Simone Martin Finds Her Top Match

What to Expect from Family Medicine Residency Programs

The 5 Most In-Demand Physicians



Hashimoto's disease

HDL-C (acronym)

High-density lipoprotein cholesterol, often called “good” cholesterol.

hemat/o (prefix)

Pertaining to blood.

HGH (acronym)

human growth hormone

Related articles:

Addressing Sexual Health with Richard Bloy, MD, FACOG

high low-density lipoprotein (LDL) cholesterol

hormone replacement pellets

Made of either estradiol or testosterone. Naturally derived from soybeans, these hormones are identical to those produced by our bodies. Hormones are pressed into small, solid pellets larger than a grain of rice, but smaller than a Tic Tac. Unlike creams, pills, or patches, pellets deliver more consistent and healthy levels of hormones into the body. They are usually inserted in the upper hip area through a tiny incision. Being made of natural compounds, pellets are completely absorbed by the body. The effects last as long as five or six months. 

Related articles:

HR (abbreviation)

Heart rate, expressed as beats per minute.


An overactive thyroid occurs when the thyroid gland produces more hormones than the body needs. This can cause increased appetite, heart palpitations, shaking, difficulty sleeping, excessive sweating, irritability, anxiety, and sometimes vision changes. 

Related articles:


When the thyroid gland does not produce enough thyroid hormones. Extremely low thyroid hormone production - which can be life threatening - is called myxedema in adults and cretinism in newborns. Typical symptoms of this thyroid disease include fatigue, sensitivity to cold temperatures, weight gain, and constipation. 

Related articles:



-itis (suffix)

 Signifies inflammation.


A patient who requires hospitalization.

inpatient care

Inpatient care requires a patient to stay in a hospital overnight and be monitored by a healthcare team throughout your treatment and recovery. 

internal medicine

Internal medicine is a broad range of care and in building relationships with patients they treat over the course of their adulthoods. As primary care doctors, they focus on disease prevention, substance abuse, mental health, and treatment of common problems of the eyes, ears, skin, nervous system, and reproductive organs, according to the American Medical Association. Internal medicine gives physicians the opportunity to combine clinical diagnostics on a wide range of complex and common conditions with a personalized and compassionate approach to medicine.


These physicians diagnose and perform non-surgical treatment of diseases and injuries of internal organ systems, such as heart disease or diabetes. Internists treat a wide range of diseases of the internal organs and provide care mainly for adults.

Internists also diagnose and treat such chronic adult conditions as diabetes, heart disease, and lung maladies. Internists are usually the first doctor a patient sees, and if necessary, they will refer patients to a specialist physician.

Related Articles:


Delivered via a vein, such as with medication or other fluid. 


The insertion of an endotracheal tube to assist a patient’s breathing.

-ismus (suffix)

Indicates a spasm or contraction.

-itis (suffix)

Signifies inflammation.

IV push

A rapid injection of medication that’s delivered intravenously.


KUB (acronym)

Kidney, Ureter, and Bladder X-ray. Commonly used for diagnosing abdominal pain.


-lysis (suffix)

Destruction or breaking down.

LDL-C (acronym)

Low-density lipoprotein cholesterol, often called “bad” cholesterol.

LFT (acronym)

Liver Function Test. Used to measure how well the liver is functioning in order to identify potential disease.

local anesthesia

Local anesthesia involves the use of injections to deaden sensation in a small part of the body. It may be used in fairly minor, highly localized operations, such as oral surgery or the removal of a mole. Local anesthesia may or may not be administered and overseen by an anesthesiologist. 

lytes (abbreviation)


-lysis (suffix)

Decomposition, destruction, or breaking down.


macro- (prefix)

Large in size.


Indicates the presence of cancerous cells.


The Latin for “in the morning.” Typically used in reference to when medication should be administered.

Match Day

Match Day is the third Friday of March when medical students find out where they have placed for their residency (if placed) at noon ET.

Related Articles:

melan/o- (prefix)

Black or dark in color.

micro- (prefix)

Small in size.

MRI (acronym)

Magnetic Resonance Imaging. A form of diagnostic imaging that uses a large magnet and radio waves to view inside of the body.

my/o- (prefix)

Related to muscle.



A neurologist is a physician trained to diagnose, analyze, and treat problems of the nervous system. The word neurology comes from the Greek word for nerves.

Related Article:


NICU (acronym)

Neonatal intensive care unit, a specialized unit that cares for premature infants.


The Latin for “at night,” often in reference to when medication should be administered.

NSAID (acronym)

Nonsteroidal Anti-inflammatory Drug. Ibuprofen, aspirin, and naproxen are NSAIDs.



The study of a particular concentration.

obstetrics and gynecology (OB/GYN)

This type of physician provides medical care relating to female reproductive systems and diagnose and treat diseases and provide care related to pregnancy and childbirth.

Related Articles:

OD (acronym)

Once daily.

-ology (suffix)

The study of a particular concentration.


Ophthalmologists are medical doctors who perform medical and surgical treatments for eye conditions. Ophthalmologists are “eye MD’s” as well as ophthalmologic surgeons. Ophthalmologists treat all diseases and disorders of the eyes. They prescribe eyeglasses and contacts and perform laser-assisted in situ keratomileusis (LASIK), small incision lenticule extraction (SMILE), or photorefractive keratectomy (PRK) surgeries to correct vision problems. Ophthalmologists also operate to treat such conditions as cataracts, diabetic retinopathy, glaucoma, macular degeneration, or strabismus (cross-eyes). Many ophthalmologists also do research on eye diseases and vision disorders.

Related Articles:


Opticians are eye care professionals but not officially “eye doctors,” and they cannot give eye exams. They are technicians trained to fit eyeglass lenses and frames and contact lenses to correct vision problems. Opticians cannot diagnose or treat eye diseases or write prescriptions. Many have one or two years of training and are licensed, but not all states require opticians to have a license.


Optometrists perform eye exams and vision tests, prescribe and dispense corrective lenses, detect eye abnormalities, and prescribe medications for eye diseases. They have a doctor of optometry (OD) degree after finishing three or more years of college and four years of optometry school.

Related Articles:

OR (acronym)

Operating Room.

-osis (suffix)

Indicates something that is abnormal.

oste/o (prefix)

Related to bone.

-otomy (suffix)

To cut into.


A patient who receives care without being admitted to a hospital.

Related Article:

outpatient care

In general, primary care physicians practice outpatient care and specialists provide inpatient care, but most physicians can treat patients in both settings. For example, your family physician will provide outpatient treatment for routine conditions.


-pathy (suffix)

Disease or disease process.

-plasty (suffix)

Surgical repair to restore or repair part of the body.

PA (acronym)

Physician Assistants are considered medical support professionals. Most PA candidates then work in medical fields to gain experience prior to applying to physician assistant master’s programs. Future PAs may work as certified nursing assistants or registered nurses, as emergency medical or emergency room technicians, as lab or medical assistants, or as paramedics or surgical technicians. PA doctors work in all the same places as physicians, but they have limited autonomy. To ensure quality of healthcare, the AMA requires PAs to work under the supervision of a doctor. Most PA doctors practice general medicine to provide primary care, but they can also advance to specialty care and concentrate on such areas as critical care, emergency or hospital medicine, or general surgery.

Related Articles:


These physicians study the causes, nature, and effects of disease, providing doctors with the information needed to treat patients.

Related Articles:


A pediatrician is a medical doctor who sees to the needs of infants, children, adolescents, and young adults. For many young people, a pediatrician is the primary care provider from birth, perhaps through the age of 18. A pediatrician in general practice must be skilled at treating common childhood ailments, from ear infections to minor injuries. Subspecialist pediatricians may have additional training in treating young people with serious or chronic illness, from developmental disorders to childhood cancers.

Being a pediatrician is about more than just treating illness. More than any other patients, children grow and change. An important part of the job of the pediatrician is to help ensure that children are achieving milestones in their growth, behavior, and skills. Educating the parents in proper care of children is also part of the pediatrician’s role. Pediatricians often advise parents in matters of health, nutrition, safety, and fitness.

Related Articles:

physical medicine and rehabilitation (PM&R)/physiatrist

Physiatrists are experts in the diagnosis, prognosis, and treatment of disorders of the musculoskeletal system. This system includes the bones that support the body, the muscles that move the body, and the connections between them. Physiatry also concerns the parts of the nervous system that control body movements and register pain. Physiatrists treat conditions affecting the brain, bones, joints, ligaments, muscles, nerves, spinal cord, and tendons. They are experts in the treatment of pain, correcting mobility limitations, and restoring functionality. These problems may result from chronic conditions, disability, illness, injury, or surgery. Physiatrists treat such conditions as carpal tunnel syndrome, chronic back pain, stress fractures, and tendonitis, as well as physical problems related to aging or growing. Physiatrists treat patients through active physical therapy exercises designed to heal and strengthen the body. They also use such passive physical therapies as the application of heat, ice, massage, and pressure to various parts of the body. Physiatrists prescribe or recommend these therapies, but they are usually performed by massage, occupational, and physical therapists.

Related Articles:

plastic surgeon

A plastic surgeon is an expert in the repair, reconstruction, or replacement of physical defects involving the breast and trunk, craniomaxillofacial structures, external genitalia, extremities, hands, musculoskeletal system, and skin, or the cosmetic enhancement of these parts of the body. Plastic surgeons also use cosmetic surgery to improve overall appearance and to optimize the outcome of reconstructive procedures. They specialize in grafting and shaping the skin and sculpting or implanting the underlying tissues.

plastic surgery

Plastic surgery treats problems of the body’s surface covering and the underlying tissues that give it structure.

Related Article:

PO (acronym)

The Latin for “per orem,” or orally.

poly- (prefix)


PR (acronym)

The Latin for “per rectum,” or rectally.

pre-op (abbreviation)


preventative medicine

Preventive medicine aims to prevent disease, disability, and death by taking a proactive approach to medicine. Preventive medicine physicians provide advice, suggestions, and recommendations to help patients maintain or improve their health and wellness. They can help patients develop healthy habits, break old habits, and reshape their approach to wellness.

Related Article:

primary care physician

These are specialists in family medicine, internal medicine, pediatrics and geriatrics and provide the primary resources — conducting routine physicals, prescribing medicines, treating minor illnesses, managing chronic conditions — for these defined populations and are typically the first point of contact, says Jones.

Family physicians are the most in-demand physicians, followed by internal medicine, according to the Doximity report.

Primary care physicians are advocates for the patient in coordinating the use of the entire health care system to benefit the patient, according to the American Academy of Family Physicians.

Related Articles:

PRN (acronym)

The Latin for “pro re nata,” or [to be taken] as needed.


The predicated outcome of disease progression and treatment.

pseudo- (prefix)

False or deceptive, usually in regard to appearance.

psych (abbreviation)

Refers to psychiatry or the psychiatric ward.


PT (acronym)

Physical therapy, a type of treatment to help patients move and feel better.

pulmon/o (prefix)

Refers to the lungs.


The measure of a pulsating artery.


Pulse Oximetry. A measure of oxygen saturation in the blood.


QDS (acronym)

the Latin for “quarter die sumendum,” or four times a day.



A radiologist is a patient who uses medical imaging technologies to diagnose and treat diseases.

Related Articles:

How to Become a Radiologist

Alicia Heidenreich Returns to Ohio Hometown to Begin First Choice Residency

regional anesthesia

Involves using nerve blocks, spinal injections, and other techniques to block sensation from a major portion of the body. It is often used for surgeries of the arms, legs, or abdomen. An epidural is a common form of regional anesthesia administered to alleviate the pain of childbirth. 


Return of disease or symptoms after a patient has recovered.

retro- (prefix)

behind or backward.

rhin/o (prefix)

Related to the nose.

Rx (abbreviation)

Prescription, usually for medication but can also signify another treatment.



Hard or hardening.


Involves the use of medications that produce a calming effect in the patient. Minimal sedation may render the patient drowsy but still able to talk. A patient put under deep sedation will not remember the surgical procedure. Sedation is often combined with other types of anesthesia to help alleviate anxiety and ensure patient comfort. 


Slowing or stopping the flow of a bodily fluid.

stat (abbreviation)



These physicians treat disease and injuries through surgery using invasive, non-invasive, and minimally invasive methods. In addition to general surgeons, there are many subspecialty areas including neurology, head and neck surgeons, and cardiothoracic surgeons who treat the heart and chest.

Related Article:


Stitches, which are used to join tissues together as they heal.


TDS (acronym)

The Latin for “ter die sumendum,” or three times a day.

therm/o (prefix)

Indicates heat.

tox screen

Toxicological analysis of the blood that identifies the drugs ingested in a suspected overdose.


The removal of an organ or tissue from one body that is implanted into another.


U/A (abbreviation)

Urinalysis. A urine test used to identify a range of disorders or disease.


A form of diagnostic imaging that uses high-frequency sound waves.

United States Medical Licensing Examination (USMLE)

The USMLE consists of three exams—all of which are required for medical licensure in the United States. 

U.S. medical students take the USMLE Step 1 exam at the end of their second year or during their third year. USMLE Step 1 covers the basics of medical practice and principles.

The USMLE Step 2 Clinical Knowledge (CK) section assesses medical students’ foundational knowledge of the clinical sciences curriculum. (Following a temporary suspension in 2020, the National Board of Medical Examiners (NBME) announced the permanent suspension of the Step 2 Clinical Skills (CS) examination in 2021. The USMLE Step 2 tests clinical knowledge only.)

USMLE Step 3 evaluates the ability to practice medicine without supervision. Most physicians take USMLE Step 3 during residency.

Related Articles:



A substance that stimulates antibody production to provide immunity against disease.


The drawing of blood from a vein.


zoonotic disease

A disease that is transmissible from animals to humans.