/ Dictionary / Index M metallocene: Meaning and Definition of Find definitions for: me•tal•lo•cene Pronunciation: (mu-tal'u-sēn"), [key] — n. Chem. an organometallic coordination compound consisting of a metal bonded to one or two rings of cyclopentadiene. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. metallo- metallograph Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language