/ Dictionary / Index P parsec: Meaning and Definition of Find definitions for: par•sec Pronunciation: (pär'sek"), [key] — n. Astron. a unit of distance equal to that required to cause a heliocentric parallax of one second of an arc, equivalent to 206,265 times the distance from the earth to the sun, or 3.26 light-years. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: parsec (Thesaurus) parse Parsee Related Content Daily Word Quiz: apogee Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language