/ Dictionary / Index C cell membrane: Meaning and Definition of Find definitions for: cell' mem"brane Pronunciation: [key] — Biol. Biol. the semipermeable membrane enclosing the cytoplasm of a cell. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. cell-mediated immunity cello 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