/ Dictionary / Index G G: Meaning and Definition of Find definitions for: G1 phase Pronunciation: [key] — Cell Biol. Cell Biol. the first growth period of the cell cycle, during interphase, in which the cell grows and cytoplasmic organelles are replicated. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: g (Thesaurus) goneness goner 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