astigmatism
/əˈstɪɡmətɪzm̩/ noun
Forms astigmatisms
- noun (optics) A defect of a lens such that light rays coming from a point do not meet at a focal point so that the image is blurred.
- noun (pathology) A disorder of the vision, usually due to a misshapen cornea, such that light does not focus correctly on the retina causing a blurred image.
Synonyms
Antonyms
Etymology
From a- (negative prefix) + stem of Ancient Greek στίγμα (stígma, “mark, point”) + -ism. Coined by English polymath William Whewell in 1846.
Webster’s 1913
- noun A defect of the eye or of a lens, in consequence of which the rays derived from one point are not brought to a single focal point, thus causing imperfect images or indistictness of vision.
Etymology [Gr. astigmatisme.]
Sources: Wiktionary · WordNet 3.0 · Webster’s 1913 — from the Wiktionary entry “astigmatism”, CC BY-SA 4.0. Details