from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A material that insulates, especially a nonconductor of sound, heat, or electricity.
- n. A device that insulates.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A substance that does not transmit heat (thermal insulator), sound (acoustic insulator) or electricity (electrical insulator).
- n. A non-conductive structure, coating or device that does not transmit sound, heat or electricity (see image)
from the GNU version of the Collaborative International Dictionary of English
- n. One who, or that which, insulates.
- n. A substance or object that insulates; a nonconductor.
from The Century Dictionary and Cyclopedia
- n. One who or that which insulates; specifically, a substance or body that interrupts the communication of electricity or heat to surrounding objects; a non-conductor; anything through which an electric current will not pass.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a material such as glass or porcelain with negligible electrical or thermal conductivity
From insulate 'to isolate' (itself from Latin insula 'island') + suffix -or (Wiktionary)