Gain a better understanding of medical terminology by searching our dictionary of more than 1,300 terms.


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  • glucose

    Dextrose. A simple six-carbon sugar naturally found in fruits, honey and blood.

  • goiter

    Enlargement of the thyroid gland.

  • gonad

    A sex gland (ovary or testis).

  • gonorrhea

    A highly contagious, sexually transmitted bacterial disease of the genital/urinary system.

  • gout

    A form of arthritis caused by deposits of uric acid crystals in the joints, usually the feet, hands and, especially,…

  • graft

    A piece of skin or other tissue used as a transplant.

  • Gram's stain

    A stain used as the first step in identifying bacteria.

  • grand mal

    A major epileptic seizure characterized by convulsions, unconsciousness and sometimes loss of urinary or bowel continence. Usually followed by a…

  • Graves' disease

    Overactive thyroid gland function (hyperthyroidism). Sometimes associated with protrusion of the eyes.

  • groin

    The region of the body where the thigh and lower abdomen meet.

  • Guillain-Barre syndrome

    A rare but reversible reaction to a viral illness or immunization that causes partial to complete loss of movement of…

  • gynecology

    The branch of medicine that deals with the study and treatment of reproductive diseases in women.

  • gynecomastia

    Overdevelopment of male breast tissue. Usually benign and temporary.

  • halitosis

    Bad breath.

  • hallucination

    The sensory perception of sights, sounds or objects that don’t really exist.

  • hammer

    The malleus, a hammer-shaped bone in the middle ear.

  • hamstring

    The tendon located in the back of the knee and lower thigh.

  • hand-foot-and-mouth disease

    A viral infection characterized by a blister-like rash of the hands, feet and mouth.

  • hangnail

    A loose piece of skin at one side of a fingernail.

  • Hansen's disease


  • harelip

    Cleft lip or palate.