/ Dictionary / Index S S phase: Meaning and Definition of Find definitions for: S phase Pronunciation: [key] — Cell Biol. Cell Biol. the period of the cell cycle prior to mitosis, during which the chromosomes are replicated. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sphalerite sphecid Related Content Daily Word Quiz: ounterfeit Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language