/ Dictionary / Index P plus sign: Meaning and Definition of Find definitions for: plus' sign" Pronunciation: [key] — Arith. Arith. the symbol (+) indicating summation or a positive quality. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. plus sight plus tick Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language