/ Dictionary / Index P plasma cell: Meaning and Definition of Find definitions for: plas'ma cell" Pronunciation: (plaz'mu-sīt"). [key] an antibody-secreting cell, derived from B cells, that plays a major role in antibody-mediated immunity. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. plasma plasmagel Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language