/ Dictionary / Index A alt: Meaning and Definition of Find definitions for: alt Pronunciation: (alt) [key] — Music. Music. —adj. high. —n. in the first octave above the treble staff. alt- Pronunciation: [key] var. ofbefore a vowel: altazimuth. alt. Pronunciation: [key] alteration. alternate. altitude. alto. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: alt (Thesaurus) Alston Alta. 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