/ Dictionary / Index R ribosomal RNA: Meaning and Definition of Find definitions for: ribosomal RNA Pronunciation: [key] — Biochem. Biochem. a type of RNA, distinguished by its length and abundance, functioning in protein synthesis as a component of ribosomes. Abbr.: rRNA Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. riboso ribosome Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language