/ Dictionary / Index S sarcoplasmic reticulum: Meaning and Definition of Find definitions for: sar•co•plas'mic retic'ulum Pronunciation: (sär"ku-plaz'mik), [key] — Cell Biol. Cell Biol. a system of membrane-bound tubules that surrounds muscle fibrils, releasing calcium ions during contraction and absorbing them during relaxation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sarcoplasm sarcoptic mange Related Content Daily Word Quiz: designate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language