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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Phrase Definition
rabies A fatal, if untreated, viral disease of mammals that's spread to humans by the bite of infected animal.
rad Radiation absorbed dose. A unit of measurement of the absorbed dose of ionizing radiation.
radiculopathy A disease or other problem affecting a nerve root.
radioisotope A radioactive form of an element. Used in certain diagnostic tests.
radiology The branch of medicine that deals with the use of x-rays.
radon A colorless, radioactive gas produced by the decay of radium. The presence of sufficient quantities of this gas in homes is linked with the development of lung cancer.
rash Visual marks or spots that appear on the skin.
Raynaud's phenomenon A circulation disorder characterized by changes of blood flow, resulting in the hands and feet becoming pale, followed by redness and pain. This condition may be caused by cold, vibrations or emotions.
recrudescence To reoccur after a temporary absence.
rectum The last portion of the large intestine.
reflux A return flow.
refraction 1. The bending of a ray or wave of light from one medium to a medium of a different density. 2. The amount of error in the eye and the correction of that error with glasses to restore normal vision.
regurgitation The return of partly digested food from the stomach to the mouth or of blood in a reverse direction through the valves of the heart.
rehabilitation The process of restoring one's ability to live as normally as possible after an injury or illness.
Reiter's syndrome A complex group of symptoms marked by inflammation of the urethra or cervix, conjunctiva and joints.
relapse The return of a disease after its apparent resolution.
REM Rapid eye movement. The phase of sleep associated with dreaming and distinguished from the other stages of sleep by rapid movement of the eyes.
remedy Anything that cures.
remission Improvement of the symptoms of a disease.
renal Having to do with the kidney.
reservoir A medical term used to describe a source of organisms causing a disease.
respiration The act or process of breathing. The process by which a living organism or cell takes in oxygen from the air or water and uses it.
resuscitation Restoring the heartbeat and/or breathing in someone who's apparently dead. Also called artificial respiration.
retardation Delay or halt of any process such as mental or physical development.
retina The innermost layer of the eyeball. The retina contains the light-sensing rods and cones used for vision.
retinopathy Degeneration of the retina.
retrobulbar Behind the eyeball.
retrovirus A virus that produces DNA from RNA (the opposite of the normal order). A group of viruses that includes HIV.
Rh factor One of the antigens present on red blood cells. Used in categorizing the type of blood a person has.
rheumatism Pain in the muscles and joints. Characterized by inflammation and stiffness. Sometimes used to describe arthritis, bursitis and sciatica.
rhinitis Inflammation of the mucous membranes of the nose.
rhinoplasty Plastic surgery of the nose.
rhinorrhea Runny nose.
rickets A condition resulting from a vitamin D deficiency in childhood. Characterized by the softening of the bones and associated deformities.
ringworm A fungal infection of the skin.
Rocky Mountain spotted fever An infectious disease spread by tick bites.
roseola infantum A common viral infection of young children. Characterized by high fever, irritability and a faint rose-colored rash that appears on the fourth day when the fever subsides.
rubella A mild childhood disease that causes fever and rash. Although rubella is mild in childhood, it's dangerous to pregnant women because it can cause birth defects. Also called German measles.
rubeola A type of measles that can lead to serious complications and death.