/ Dictionary / Index S second of arc: Meaning and Definition of Find definitions for: sec'ond of arc' Pronunciation: [key] second (def. 4). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. secondo second papers Related Content Daily Word Quiz: hedonist Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language