insulation

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

• noun The act of insulating or the state of being insulated.
• noun A material or substance used in insulating.

from The Century Dictionary.

• noun The act of insulating or detaching, or the state of being detached, from other objects.
• noun In electricity and thermotics, that state in which the communication of electricity or heat to other bodies is prevented by the interposition of a non-conductor; also, the material or substance which insulates. See insulate and insulator.
• noun The act of setting free from combination, as a chemical body; isolation.

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

• noun The act of insulating, or the state of being insulated; detachment from other objects; isolation.
• noun (Elec. & Thermotics) The act of separating a body from others by nonconductors, so as to prevent the transfer of electricity or of heat; also, the state of a body so separated.
• noun The material or substance used to insulate from either electrical or thermal conduction.

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

• noun The act of insulating, or the state of being insulated; detachment from other objects; isolation.
• noun Any of a variety of materials designed to reduce the flow of heat, either from or into a building.
• noun engineering The act of separating a body from others by nonconductors, so as to prevent the transfer of electricity, heat, or sound
• noun engineering The state of a body so separated.
• noun electrical a medium in which it is possible to maintain an electrical field with little supply of energy from additional sources.

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

• noun the act of protecting something by surrounding it with material that reduces or prevents the transmission of sound or heat or electricity
• noun the state of being isolated or detached
• noun a material that reduces or prevents the transmission of heat or sound or electricity