Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

Medical Dictionary

lens

noun

Medical Definition of lens

  1. 1:  a curved piece of glass or plastic used singly or combined in eyeglasses or an optical instrument (as a microscope) for forming an image by focusing rays of light

  2. 2:  a device for directing or focusing radiation other than light (as sound waves, radio microwaves, or electrons)

  3. 3:  a highly transparent biconvex lens-shaped or nearly spherical body in the eye that focuses light rays entering the eye typically onto the retina, lies immediately behind the pupil, is made up of slender curved rod-shaped ectodermal cells in concentric lamellae surrounded by a tenuous mesoblastic capsule, and alters its focal length by becoming more or less spherical in response to the action of the ciliary muscle on a peripheral suspensory ligament

  4. lensed adjective
    lens·less adjective



Illustration of lens

Variants of lens

also lense \ˈlenz\play


Seen and Heard

What made you want to look up lens? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

February 6, 2016

an official order, decree, or edict

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image1037863653

Which of the following refers to thin, bending ice, or to the act of running over such ice?

pince-nez kittly-benders spindrift duvet
Name That Thing

10 quick questions: hear them, spell them, and see how your skills compare to the crowd.

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ