/ Dictionary / Index A alter: Meaning and Definition of Find definitions for: al•ter Pronunciation: (ôl'tur), [key] — v.t. to make different in some particular, as size, style, course, or the like; modify: to alter a coat; to alter a will; to alter course. to castrate or spay. —v.i. to change; become different or modified. Al•ter Pronunciation: (ôl'tur), [key] 1807–81, U.S. physicist. alter. Pronunciation: [key] alteration. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: alter (Thesaurus) Altdorfer alterable Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language