astigmatism (n.)

"defect in the structure of the eye whereby the rays of light do not converge to a point upon the retina," 1849, coined by the Rev. William Whewell, English polymath, from Greek a- "without" (see a- (3)) + stigmatos genitive of stigma "a mark, spot, puncture," from PIE root *steig- "to stick; pointed" (see stick (v.)).