/ Dictionary / Index N nuclei: Meaning and Definition of Find definitions for: nu•cle•i Pronunciation: (n'klē-ī", ny'-), [key] — n. pl. of Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: nuclei (Thesaurus) nucleate nucleic acid 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