/ Dictionary / Index H heptanone: Meaning and Definition of Find definitions for: hep•ta•none Pronunciation: (hep'tu-nōn"), [key] — n. Chem. any of three isomeric ketones, CHO, derived from heptane. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. heptangular heptarchy Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language