/ Dictionary / Index I infra: Meaning and Definition of Find definitions for: in•fra Pronunciation: (in'fru), [key] — adv. below, esp. when used in referring to parts of a text. Cf. supra. infra- Pronunciation: [key] a prefix meaning “below,” used, with second elements of any origin, in the formation of compound words: infrasonic; infrared. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: infra (Thesaurus) infotainment infract Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language