aperture

aperture definition - medical

ap·er·ture (ăpˈər-chər)

noun
  1. An opening, such as a hole, gap, or slit.
  2. A usually adjustable opening in an optical instrument, such as a microscope, a camera, or a telescope, that limits the amount of light passing through a lens or onto a mirror.
  3. The diameter of such an opening.
  4. The diameter of the objective of a telescope or microscope.

Related Forms:

  • apˈer·turˌal adjective

The American Heritage® Medical Dictionary Copyright © 2009 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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