Glossary index
Medical terms beginning with A
Browse medical definitions and meanings in the complete glossary, or choose a letter to narrow the list.
511 medical terms in this glossary begin with the letter A, from aneurysm onward. Every entry gives a plain-language definition, and most add a pronunciation, the word parts it is built from, and related terms.
This is also the place to look for medical words, health words, anatomy terms and disease names starting with A.
A terms
511 results-
A weakened patch of artery wall stretched outward by the pressure inside it, usually silent until the day it is not.
-
The root of any of a group of herbs called Angelica.
-
Chest discomfort that arrives on exertion and leaves at rest is the heart complaining about a supply line that has narrowed.
-
Angiogenesis is the normal process of forming new blood vessels from existing ones, a process tumors also exploit to secure their own blood supply.
-
A drug that starves growth by cutting the signal for new plumbing, given to far more people for eye disease than for cancer.
-
The picture shows the space inside a vessel rather than its wall, so it maps the channel that blood actually has left to travel through.
-
A procedure to x-ray blood vessels.
-
An aggressive (fast-growing) type of T-cell non-Hodgkin lymphoma marked by enlarged lymph nodes and hypergammaglobulinemia (increased antibodies in the blood).
-
A harmless-sounding kidney growth of fat, muscle and tangled vessels whose real danger is not spread but sudden heavy bleeding.
-
No incision ever reaches the artery: the whole repair travels there through a puncture, which is why recovery bears no resemblance to bypass surgery.
-
Angiosarcoma is a rare cancer arising from cells lining blood or lymph vessels, sometimes linked to chronic lymphedema or specific chemical exposures.
-
A drug that is used to lower blood pressure.
-
An anticancer drug that belongs to the family of drugs called mitotic inhibitors.
-
An animal with a disease either the same as or like a disease in humans.
-
A laboratory experiment using animals to study the development and progression of diseases.
-
What makes it therapy rather than a visit is the written goal, the trained handler and the record of whether it worked.
-
An aggressive (fast-growing) disease in which too many myeloblasts (immature white blood cells that are not lymphoblasts) are found in the bone marrow and blood.
-
A substance that is being studied in the treatment of cancer.
-
An abnormal loss of the appetite for food.
-
An anticancer drug that belongs to the family of drugs called antineoplastic antibiotics.
-
Occupying the lock without turning it: the value of the drug lies entirely in what it prevents, never in what it does.
-
anterior
/ an-TEER-ee-or /Situated toward the front of the body or a body structure.
-
A procedure in which a tube is inserted into the chest to view the tissues and organs in the area between the lungs and between the breastbone and heart.
-
The area in the front part of the chest between the lungs.
-
Surgery to remove the urethra, lower part of the ureters, uterus, cervix, vagina, and bladder.
-
A disease in which malignant (cancer) cells are found in the part of the urethra (the tube through which urine leaves the body) that is closest to the outside of the body.
-
An anticancer drug that belongs to the family of drugs called anticancer antibiotics.
-
A family of red-colored chemotherapy drugs, among the most effective available and among the hardest on the heart.
-
A type of anticancer drug.
-
A monoclonal antibody linked to a toxic substance.
-
A vaccine made of antibodies that see other antibodies as the antigen and bind to it.
-
Anti-inflammatory describes a substance or treatment that reduces inflammation, the body's protective but sometimes damaging response to injury or irritation.
-
A substance being studied in the treatment of some types of cancer.
-
A drug that stops male hormones being heard, either by blocking the receiver or by cutting off the supply.
-
Treatment with drugs used to block production or interfere with the action of male sex hormones.
-
Antiangiogenesis refers to blocking the formation of new blood vessels, a process tumors depend on to grow and spread.
-
A word for the brake on blood vessel growth, one the body applies by default and drugs press harder in eye disease and cancer.
-
A drug used to treat symptoms of anxiety, such as feelings of fear, dread, uneasiness, and muscle tightness, that may occur as a reaction to stress.
-
Something that prevents apoptosis.
-
A substance that kills bacteria or stops them from growing and causing disease.
-
Bacteria gain resistance by mutation and by trading genes with one another, which is how a reliable drug stops working.
-
Five classes exist, and which one is present says a good deal about where an immune response is and how old it is.
-
Treatment that borrows the immune system's own targeting protein, manufactured in bulk and aimed at one chosen molecule.
-
A type of immune reaction in which a target cell or microbe is coated with antibodies and killed by certain types of white blood cells.
-
The immune system's way of using antibodies as handles, letting killer cells grip a marked target and destroy it.
-
Describes a drug or effect that works against cachexia (loss of body weight and muscle mass).
-
A type of anticancer drug that blocks cell growth by interfering with DNA, the genetic material in cells.
-
Treatment to stop or prevent cancer.
-
Having to do with preventing or delaying the development of cancer.
-
An anticoagulant reduces the blood's tendency to clot, used to prevent or treat dangerous clots in conditions such as atrial fibrillation and deep vein thrombosis.
-
Anticonvulsants include several distinct drug classes, some of which are also prescribed for other conditions such as chronic pain or mood disorders.
-
Blood levels rise within a day yet mood shifts take weeks, a gap suggesting slower brain adaptation rather than a simple chemical top-up.
-
A substance used to treat diarrhea (frequent and watery bowel movements).
-
Antiemetics work through several different mechanisms depending on the drug class, from blocking specific brain receptors to countering inner ear signals.
-
A drug or other substance used to prevent or stop seizures or convulsions.
-
A substance that keeps cells from making or using estrogen (a hormone that plays a role in female sex characteristics, the menstrual cycle, and pregnancy).
-
A substance that blocks the activity of folic acid.
-
Harder to design than an antibiotic, because a fungal cell is built much like a human one and shares most of its machinery.
-
An antigen is any substance the immune system recognizes as foreign, prompting it to mount a targeted immune response, including antibody production.
-
Cells that decide whether an immune response begins, by carrying a fragment of an intruder to a lymph node for T cells to inspect.
-
A vaccine made of antigens and antigen-presenting cells (APCs).
-
A laboratory test to identify antibodies that can bind to the surface of red blood cells or platelets and destroy them.
-
The word usually means an allergy tablet, though the drugs that quiet stomach acid block a histamine receptor too.
-
Treatment with drugs, surgery, or radiation in order to block the production or action of a hormone.
-
Serum from blood that contains antibodies that bind to human T cells.
-
A drug that works by imitation, close enough to a natural building block to be taken up and wrong enough to jam the machinery.
-
An antimicrobial is any substance that kills or stops the growth of microorganisms, including bacteria, viruses, fungi, and parasites.
-
A type of drug that blocks cell growth by stopping mitosis (cell division).
-
A type of drug that blocks cell growth by stopping mitosis (cell division).
-
Antineoplastic drugs form the basis of chemotherapy, working through several distinct mechanisms to slow, damage, or destroy dividing cancer cells.
-
A type of anticancer drug that blocks cell growth by interfering with DNA, the genetic material in cells.
-
A set of compounds promoted for decades as a cancer treatment, still without approval or an independent trial showing benefit.
-
A type of gene that makes a protein called a tumor suppressor protein that helps control cell growth.
-
Antioxidants are substances that neutralize unstable molecules called free radicals, though supplement studies have not consistently shown they prevent disease.
-
A drug used to treat infections caused by bacteria and parasites.
-
A substance that prevents cells from making or using progesterone (a hormone that plays a role in the menstrual cycle and pregnancy).
-
Damping dopamine quiets hallucinations and delusions, but the same block reaches movement and hormone pathways, which is where the side effects begin.
-
A type of drug used to treat symptoms of psychosis.
-
Because HIV can develop resistance to a single drug relatively quickly, antiretroviral therapy nearly always combines medications from more than one class.
-
Small pieces of DNA or RNA that can bind to specific molecules of RNA.
-
A substance that has been studied in the treatment of cancer and is being studied in the treatment of rheumatoid arthritis and certain skin conditions.
-
A short synthetic strand designed to pair with one chosen message inside a cell and either destroy it or reroute it.
-
A description of conduct that disregards other people's rights, and not, in clinical use, a word for being shy or private.
-
Serum from blood that contains antibodies that bind to human T cells.
-
Describes a drug or effect that works against tuberculosis (a contagious bacterial infection that usually affects the lungs).
-
Antitumor describes a treatment or biological effect that works to shrink, slow, or destroy an existing tumor.
-
A type of anticancer drug that blocks cell growth by interfering with DNA, the genetic material in cells.
-
Narrow by design: a drug that halts one virus usually does nothing whatsoever against an unrelated one.
-
The opening of the rectum to the outside of the body.
-
A useful alarm system that has become a problem when it fires without a threat, or keeps firing after one has passed.
-
An anxiolytic is a medication used to relieve anxiety symptoms, most familiarly a benzodiazepine that enhances a calming brain chemical's effect.
-
A drug used to treat symptoms of anxiety, such as feelings of fear, dread, uneasiness, and muscle tightness, that may occur as a reaction to stress.
-
Nearly every artery in the body branches from this one vessel, whose elastic wall keeps blood moving between heartbeats.
-
Surgery in which a healthy blood vessel taken from another part of the body is used to make a new path for blood around a blocked artery leading to the heart.
-
A substance being studied in the treatment of soft tissue and bone cancers.
-
A substance being studied in the treatment of head and neck cancer.
-
A vaccine made of antigens and antigen-presenting cells (APCs).
-
A drug used to treat prostate cancer that has spread.
-
aphasia
/ uh-FAY-zhuh /An acquired impairment in producing or understanding language.
-
Apheresis is a procedure that separates and collects a specific blood component while returning the remaining blood to the donor or patient.