Glossary index
Medical terms beginning with H
Browse medical definitions and meanings in the complete glossary, or choose a letter to narrow the list.
230 medical terms in this glossary begin with the letter H, from H. pylori 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 H.
H terms
230 results-
A type of bacterium that causes inflammation and ulcers in the stomach or small intestine.
-
A substance being studied in the treatment of several types of lymphoma.
-
The combination approach that turned HIV infection from a fatal illness into a manageable long-term condition.
-
A hair follicle is the tunnel shaped skin structure surrounding a hair root, distinct from the visible hair shaft that extends above the skin surface.
-
A slow-growing blood cancer named for the fringed look of its cells, marked by a large spleen and low counts across the board.
-
Which sense is involved narrows the cause sharply, because heard voices and seen figures point in quite different clinical directions.
-
Surgery for breast cancer in which the breast, chest muscles, and all of the lymph nodes under the arm are removed.
-
A benign (not cancer) growth made up of an abnormal mixture of cells and tissues normally found in the area of the body where the growth occurs.
-
A condition marked by pain, swelling, numbness, tingling, or redness of the hands or feet.
-
A plant whose seeds and root have been used in some cultures to treat certain medical problems.
-
The front, bony part of the roof of the mouth.
-
An autoimmune condition of the thyroid gland (a gland located beneath the larynx).
-
An autoimmune condition of the thyroid gland (a gland located beneath the larynx).
-
The fruit of the hawthorn tree or bush.
-
A measure of how often a particular event happens in one group compared to how often it happens in another group, over time.
-
HCA refers to heterocyclic amines, chemical compounds formed when meat is cooked at high temperatures and classified as possible carcinogens.
-
A substance being studied in the treatment of several types of lymphoma.
-
HCP most often abbreviates healthcare provider or healthcare professional, though the same letters also denote a health care proxy, an unrelated advance directive role.
-
A substance being studied in the treatment of brain cancer.
-
An enzyme that removes a small molecule called an acetyl group from histones (proteins found in chromosomes).
-
The short form used in oncology for drugs acting on the packaging of DNA rather than on the sequence written in it.
-
Cancer that arises in the head or neck region (in the nasal cavity, sinuses, lips, mouth, salivary glands, throat, or larynx [voice box]).
-
A nursing-derived practice whose claimed mechanism, a flow of vital energy, has never been detected by any physical measurement.
-
One word stretched across a solo therapist and a thousand bed hospital, useful in billing and records precisely because it specifies nothing.
-
The person chosen in advance to speak for a patient who can no longer speak, and the document that appoints them.
-
In a clinical study, a person who does not have the disorder or disease being studied.
-
The muscle of the heart starves while the person is usually awake and talking, which is what separates it from a cardiac arrest.
-
Tumors that spread to the heart from cancer elsewhere in the body are considerably more common than cancer that originates in the heart itself.
-
A name that frightens more than it explains: the heart has not stopped, it has fallen behind what the body asks of it.
-
Most murmurs are harmless noise from normal blood flow, which is why the character of the sound matters more than its presence.
-
The name is a misnomer, and the overlap with chest pain from the heart is exactly why the two are so often confused.
-
Molecular chaperones named after the heat experiment that revealed them, though they work constantly and not only in a crisis.
-
An herb used in traditional Chinese medicine to treat certain medical problems.
-
A detailed picture of areas inside the body.
-
A type of therapy in which radiation is aimed at a tumor from many different directions.
-
A type of bacterium that causes inflammation and ulcers in the stomach or small intestine.
-
A type of immune cell that stimulates killer T cells, macrophages, and B cells to make immune responses.
-
A protein found in the outer coat of paramyxoviruses.
-
A type of cancer involving blood vessels and soft tissue.
-
A rare cancer of the cells lining blood vessels, which is why it can begin almost anywhere in the body.
-
Originating in the blood or spread through the bloodstream.
-
A cancer of the blood or bone marrow, such as leukemia or lymphoma.
-
The specialist called when a routine blood count stops making sense, whether the answer turns out to be cancer or not.
-
A bruise stains the tissue, while a hematoma occupies space, and the trouble it causes comes mostly from what it presses on.
-
Every red cell, white cell and platelet traces back to one kind of stem cell, replaced constantly because none of them last.
-
A group of proteins that causes blood cells to grow and mature.
-
Tissue in which new blood cells are formed.
-
A drug used in photodynamic therapy that is absorbed by tumor cells.
-
Color is a poor guide here, since beets and some medicines redden urine while a serious cause may leave it looking normal.
-
The iron-holding ring that lets blood carry oxygen, and the same ring that turns a bruise yellow as it is dismantled.
-
A condition in which one side of the body or a part of one side is larger than the other.
-
An operation to remove one side of the larynx (voicebox).
-
A condition in which the body takes up and stores more iron than it needs.
-
Four protein chains around four iron atoms, arranged so that picking up one oxygen molecule makes the next three easier to catch.
-
Hemophagocytic lymphohistiocytosis is a rare, life-threatening syndrome of overwhelming immune activation that damages organs and destroys blood cells.
-
Bleeding is not faster than usual, only harder to stop, because the clot that forms is too fragile to hold.
-
In heavy bleeding it is the flooding of the airways, not the volume of blood lost, that does the damage.
-
In medicine, loss of blood from damaged blood vessels.
-
An enlarged or swollen blood vessel, usually located near the anus or the rectum.
-
Fast on, fast off and reversible with an antidote, which is why hospitals reach for it when clotting risk may change within hours.
-
Hepatectomy removes part or all of the liver, often performed to treat tumors, donate a liver segment, or address severe injury.
-
Hepatic describes anything relating to, affecting, or associated with the liver, including its blood vessels, tissue, and function.
-
A procedure to deliver chemotherapy directly to the liver.
-
A block in blood flow to the liver.
-
The major blood vessel that carries blood to the liver.
-
The vein that carries everything absorbed from the gut straight to the liver before the rest of the body sees it.
-
A condition in which some of the veins in the liver are blocked.
-
One word covering many diseases: the letter attached to a viral hepatitis says far more about its course than the word itself does.
-
A liver virus whose outcome turns less on the virus itself than on the age of the person it first infects.
-
Hepatitis C virus is a bloodborne virus that infects the liver, often persisting for years and gradually causing scarring if left untreated.
-
A virus too incomplete to infect anyone by itself, dependent on hepatitis B to supply the coat it cannot build.
-
First noticed as a puzzling new marker in liver cells of people with hepatitis B, later shown to be a separate virus.
-
A liver virus carried by contaminated water and by undercooked meat, usually brief but dangerous in late pregnancy.
-
A virus that may be found in patients with hepatitis (inflammation of the liver).
-
Having to do with the liver, bile ducts, and/or gallbladder.
-
A tumor of immature liver tissue in very young children, and among the more treatable childhood cancers when caught early.
-
Hepatocellular carcinoma is the most common primary liver cancer, arising directly from liver cells and closely linked to cirrhosis and chronic viral hepatitis.
-
hepatocyte
/ heh-PA-toh-site /A hepatocyte is the main parenchymal cell of the liver and carries out many of the organ’s metabolic, synthetic, and detoxifying functions.
-
hepatoma
/ HEH-puh-TOH-muh /Hepatoma is an older, imprecise term for a liver tumor and has often been used to mean hepatocellular carcinoma.
-
hepatomegaly
/ HEH-puh-toh-MEH-guh-lee /Hepatomegaly is enlargement of the liver beyond its expected size.
-
The protein found on the surface of some cells and to which epidermal growth factor binds, causing the cells to divide.
-
A protein involved in normal cell growth.
-
An herb used in traditional Chinese medicine to treat certain medical problems.
-
Herbal describes products or remedies derived from plants, which can carry measurable pharmacologic effects and interactions despite a natural origin.
-
A type of medicine that uses roots, stems, leaves, flowers, or seeds of plants to improve health, prevent disease, and treat illness.
-
Plant products sold under food rules rather than drug rules, which is what makes their strength and contents so variable.
-
A herbicide is a chemical formulated to kill unwanted plants, and exposure to certain herbicides can also cause toxicity in humans.
-
Present from the first cell onward, even when nothing shows for decades, and never the same claim as present at birth.
-
A gene change in a body's reproductive cell (egg or sperm) that becomes incorporated into the DNA of every cell in the body of the offspring.
-
Families share more than genes, and separating the inherited from the merely shared is the harder half of reading a family history.
-
The bulging of an internal organ through a weak area or tear in the muscle or other tissue that holds it in place.
-
A substance made from morphine.
-
A herpesvirus is any member of a large family of viruses that establish lifelong latent infection in the body after initial exposure.
-
A chemical that is formed when meat, poultry, or fish is cooked at high temperatures, such as frying, broiling, and barbecuing.
-
One word doing three jobs, in radiology, pathology and research, and the reason a single sample can misrepresent a whole tumor.
-
Derived from a different source or species.
-
Derived from a different source or species.
-
A substance being studied in the treatment of some types of cancer.
-
A substance being studied in the treatment of some types of cancer.
-
A type of virus that causes herpes infections and has DNA as its genetic material.