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


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All terms that start with the letter S
  • strabismus

    A deviation in which both eyes aren’t trained on the same spot. Also called crossed eyes or lazy eye.

  • strain

    1. To filter. 2. Excessive effort. 3. Overstretching a portion of a muscle. 4. Within a species, a group of…

  • stress

    1. Pressure; strain. 2. Any condition that causes mental or physical strain or tension.

  • stridor

    A harsh or squeaky sound in breathing, often associated with a blocked larynx.

  • stroke

    Deprivation of the blood supply to the brain due to blockage of a blood vessel. Results in unconsciousness, paralysis or…

  • stye

    Infection of one of the sebaceous glands of the edge of the eyelid.

  • subcutaneous

    Just beneath the skin.

  • subdural

    Beneath the dura mater, the covering of the brain.

  • subliminal

    Below the threshold of conscious awareness.

  • subluxation

    Partial dislocation.

  • subungual

    Beneath a nail.

  • sucrose

    A natural sugar obtained from sugar cane and sugar beets used as a sweetening agent. Also called table sugar.

  • suicide

    Taking one’s own life.

  • sunburn

    A skin inflammation caused by prolonged exposure to ultraviolet radiation from the sun, tanning beds or other sources.

  • sunstroke

    A serious failure of the body’s heat-regulating mechanism resulting from excessive exposure to intense heat. Also called heat stroke.

  • superinfection

    Sudden growth of a different type of bacteria than the type originally diagnosed and treated. This is a common cause…

  • suppository

    A cone-shaped solid mass of medication designed to be placed in the rectum or vagina.

  • surfactant

    A substance produced in the lungs that reduces surface tension and helps keep the small air sacs open.

  • surrogate

    A substitute.

  • suture

    1. The joining together of certain vertebrate bones, especially of the skull. 2. A stitch or stitches made to close…

  • synapse

    The tiny space between two nerve cells that allows the transmission of a nerve impulse.