11 letters · 16 points in Scrabble
noun (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea; common in nearsighted people
noun (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point
originFrom a- (negative prefix) + stem of Ancient Greek στίγμα (stígma, “mark, point”) + -ism. Coined by English polymath William Whewell in 1846.
Etymology from Wiktionary, CC BY-SA 3.0