dilator

/daɪˈleɪtər/
noun
  1. A medical instrument used to widen a passage or opening in the body.
    • She needed a dilator to help treat the narrowing in her esophagus.
    • The nurse sterilized the dilator before the procedure.
    • The surgeon used a dilator to gently open the patient's artery.
  2. A muscle that opens or widens a body part, such as the pupil of the eye.
    • Certain drugs can stimulate the dilator in the eye, causing the pupil to widen.
    • The doctor explained how the dilator works to control the amount of light entering the eye.
    • The dilator muscle of the iris makes the pupil larger in dim light.
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