The Collaborative International Dictionary of English v.0.48:

Insulate \In"su*late\, v. t. [imp. & p. p. Insulated; p. pr. &
   vb. n. Insulating.] [L. insulatus insulated, fr. insula
   island. See Isle, and cf. Isolate.]
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   1. To make an island of. [Obs.] --Pennant.
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   2. To place in a detached situation, or in a state having no
      communication with surrounding objects; to isolate; to
      separate.
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   3. (Elec. & Thermotics) To prevent the transfer of
      electricity or heat to or from (bodies) by the
      interposition of nonconductors.
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   Insulating stool (Elec.), a stool with legs of glass or
      some other nonconductor of electricity, used for
      insulating a person or any object placed upon it.
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