/ Dictionary / Index L long-chain: Meaning and Definition of Find definitions for: long-chain Pronunciation: (lông'chān", long'-), [key] — adj. Chem. pertaining to molecules composed of long chains of atoms, or polymers composed of long chains of monomers. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: long-chain (Thesaurus) long-case clock long clam Related Content Daily Word Quiz: lunar Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language