/ Dictionary / Index U unidirectional: Meaning and Definition of Find definitions for: u•ni•di•rec•tion•al Pronunciation: (y"ni-di-rek'shu-nl, -dī-), [key] — adj. operating or moving in one direction only; not changing direction: a unidirectional flow. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: unidirectional (Thesaurus) unidimensional uniface Related Content Daily Word Quiz: inutiae Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language