/ Dictionary / Index T tangential motion: Meaning and Definition of Find definitions for: tangen'tial mo'tion Pronunciation: [key] — Astron. Astron. the component of the linear motion of a star with respect to the sun, measured along a line perpendicular to its line of sight and expressed in miles or kilometers per second. Also calledCf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. tangential tangerine Related Content Daily Word Quiz: diligent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language