astigmatism, astigmia
(noun) (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point
astigmatism, astigmia
(noun) (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea; common in nearsighted people
Source: WordNet® 3.1
astigmatism (countable and uncountable, plural astigmatisms)
(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.
(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.
• astigmia
Source: Wiktionary
A*stig"ma*tism, n. Etym: [Gr. astigmatisme.] (Med. & Opt.)
Definition: 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.
Note: The term is applied especially to the defect causing images of lines having a certain direction to be indistinct, or imperfectly seen, while those of lines transverse to the former are distinct, or clearly seen.
Source: Webster’s Unabridged Dictionary 1913 Edition
11 February 2025
(noun) shad-like food fish that runs rivers to spawn; often salted or smoked; sometimes placed in genus Pomolobus
The Boston Tea Party helped popularize coffee in America. The hefty tea tax imposed on the colonies in 1773 resulted in America switching from tea to coffee. In the lead up to the Revolutionary War, it became patriotic to sip java instead of tea. The Civil War made the drink more pervasive. Coffee helped energize tired troops, and drinking it became an expression of freedom.
