D defs.my
Entry 3 senses Webster, 1913

Insulate

/ĭn'-səl-ātˌ/ · In·su·late · IPA /ˈɪnsʊleɪt/
01 v. t. To make an island of.
imp. & p. p. Insulated; p. pr. & vb. n. Insulating
  1. 1.
    To make an island of.[Obs.]
  2. 2.
    To place in a detached situation, or in a state having no communication with surrounding objects; to isolate; to separate.
  3. 3.
    To prevent the transfer of electricity or heat to or from (bodies) by the interposition of nonconductors.(Elec. & Thermotics)
Phrases & compounds
Insulating stool — a stool with legs of glass or some other nonconductor of electricity, used for insulating a person or any object placed upon it.