Dictionary

Enter a word or phrase below to search our online dictionary of over 1,300 general medical terms, or click on a letter of the alphabet to view all terms beginning with that letter:

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Search for 'L'

Phrase Definition
labia Lip-shaped structures; often used to describe the outer folds of the female genitalia.
labyrinth The system of interconnecting canals and cavities in the inner ear. Plays an important role in hearing and in balance.
laceration A wound caused by a cut from a sharp instrument or the tearing of body tissue.
lacrimation Discharge of tears. "Watering" eyes.
lactase An enzyme that converts the milk sugar lactose into glucose and galactose.
lactation Secretion of milk by the breasts.
lactose Milk sugar.
laryngitis Inflammation of the larynx, resulting in a temporary loss of voice.
larynx The voice box.
lateral Toward the side, sideways.
lavage Washing out of an organ, especially the stomach.
Legg-Calve-Perthes disease Perthes disease A disease in which the blood supply to the femur is reduced, causing the bone to collapse.
lens 1. A curved glass used to bring together or spread rays of light. 2. The transparent organ lying behind the iris and pupil that focuses light on the retina of the eye.
leprosy A progressive infectious disease that attacks the skin, flesh and nerves; characterized by nodules, ulcers, scaly scabs, deformities and the eventual loss of sensation. Also called Hansen's disease.
lesion Any damage to a tissue. Marks, spots, moles or other problems of the skin.
lethargy A lack of energy; sluggishness, dullness or apathy.
leukemia Cancer of the tissues in the bone marrow, spleen and lymph nodes.
leukocytes White blood cells, the blood cells responsible for fighting infection.
leukopenia A lower than normal number of leukocytes in the blood.
leukopheresis Selective removal of the white blood cells from a donor's blood. The other components of the blood are then returned to the donor.
leukoplakia Thick, white patches in the mouth that may become malignant.
lichen Any of various skin diseases characterized by sores and enlarged skin markings.
ligament A tough band of connective tissue connecting bones or holding organs in place.
ligature A wire or thread used to tie off blood vessels or to close incisions or wounds.
lightening The feeling of decreased abdominal pressure during the last few weeks of pregnancy caused by the uterus dropping into the pelvis.
limbus Margin, or border. The margin of the cornea where it contacts the sclera.
lingua Tongue.
lipid Cholesterol, triglycerides and related substances.
lipocyte A fat cell.
lipolysis The splitting up, or destruction, of fat.
lipoma Fatty tumor.
lipoprotein Any of a group of proteins combined with a lipid that allow lipids to be transported in the circulatory system.
liposuction A surgical procedure that changes body shape by removing fat cells.
litholysis Breaking up of a stone, such as a gallstone.
lithotripsy A procedure to break up kidney stones into smaller pieces that can more easily pass out of the body.
liver The large organ in the upper right abdomen that functions in digestion and storage of food, disposal of worn-out red blood cells and detoxification of the body.
lobe 1. The fleshy lower part of the ear. 2. A well-defined portion of an organ.
lobectomy Surgical removal of the lobe of an organ.
lobotomy A surgical operation in which a lobe of the brain, especially the frontal lobe of the cerebrum, is cut into or across. This used to be a common procedure to calm selected psychotic patients before the development of modern tranquilizers.
lochia The discharge from the vagina that occurs for several days to weeks after childbirth.
lockjaw Tetanus infection.
loins The portion of the back between the rib cage and pelvis.
lordosis Forward curvature of the spine, producing a hollow in the back.
LSD Lysergic acid diethylamide. A hallucinogenic drug.
lumbago Pain in the lower back.
lumbar Having to do with the lower back, the loins.
lungs The main respiratory organs in the chest where blood is oxygenated.
lupus erythematosus A usually chronic inflammatory disease that causes abnormalities of blood vessels and connective tissue in various parts of the body.
luteinizing hormone A hormone secreted by the anterior pituitary gland, responsible for stimulating ovulation in the female and testosterone production in the male.
Lyme disease A disease spread by deer ticks characterized at first by a skin rash, headache and fever, and later by arthritis and heart damage.
lymph Consists primarily of a clear, yellowish fluid and white blood cells. Found in the lymphatic system.
lymph node Any of many small, compact structures lying in groups along the course of the lymphatic vessels and producing lymphocytes.
lymphadenitis Inflammation of the lymph nodes.
lymphangitis Inflammation of a lymphatic vessel.
lymphatic system The vessels and structures involved in carrying lymph from the tissues to the blood.
lymphedema Swelling of tissue because of the buildup of too much lymph fluid.
lymphocyte A type of leukocyte (white blood cell) involved in the production of antibodies and the development of immunity.
lymphoma A malignant tumor of the lymphoid tissues.