/ Dictionary / Index S sphenodon: Meaning and Definition of Find definitions for: sphe•no•don Pronunciation: (sfē'nu-don", sfen'u-), [key] — n. tuatara. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: sphenodon (Thesaurus) spheno- sphenogram Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language