/ Dictionary / Index C cyclopentadiene: Meaning and Definition of Find definitions for: cy•clo•pen•ta•di•ene Pronunciation: (sī"klu-pen"tu-dī'ēn, sik"lu-), [key] — n. a colorless liquid, CH, derived by the distillation of coal tar: used chiefly in the manufacture of insecticides and resins. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. cyclopedic cyclopentane Related Content Daily Word Quiz: arboreal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language