/ Dictionary / Index N nucleoid: Meaning and Definition of Find definitions for: nu•cle•oid Pronunciation: (n'klē-oid", ny'-), [key] — Microbiol. Microbiol. —n. the central region in a prokaryotic cell, as a bacterium, that contains the chromosomes and that has no surrounding membrane. —adj. resembling a nucleus. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. nucleocapsid nucleolar Related Content Daily Word Quiz: portent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language