vinyl

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The univalent hydrocarbon group CH₂=CH, derived from ethylene.
• noun Any of various compounds containing the vinyl group, typically highly reactive, easily polymerized, and used as basic materials for plastics.
• noun Any of various typically tough, flexible, shiny plastics, often used for coverings and clothing.
• noun Phonograph records considered as a group.
• idiom (on vinyl) In the medium of phonograph recordings.

from The Century Dictionary.

• noun The compound univalent radical CH₂CH, which appears characteristic of many ethylene derivatives.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) The hypothetical radical C2H3, regarded as the characteristic residue of ethylene and that related series of unsaturated hydrocarbons with which the allyl compounds are homologous.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun chemistry, uncountable The univalent radical CH2=CH−, derived from ethylene
• noun countable Any of various compounds and substances containing the vinyl radical, especially various tough, flexible, shiny plastics
• noun collectively, uncountable Phonograph records as a medium
• adjective chemistry containing the vinyl radical
• adjective Made of polyvinyl chloride.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun shiny and tough and flexible plastic; used especially for floor coverings
• noun a univalent chemical radical derived from ethylene