insulator vs bushing

insulator and bushing both are nouns.

Word	Noun	Adjective	Verb	Adverb
insulator	Yes	No	No	No
bushing	Yes	No	No	No

As nouns, bushing is a hyponym of insulator; that is, bushing is a word with a more specific, narrower meaning than insulator:

insulator: a material such as glass or porcelain with negligible electrical or thermal conductivity
bushing: an insulating liner in an opening through which conductors pass

Other hyponyms of insulator include mineral wool, rock wool, glass wool, ferroelectric material.

insulator (noun)	bushing (noun)
a material such as glass or porcelain with negligible electrical or thermal conductivity	a cylindrical metal lining used to reduce friction
	an insulating liner in an opening through which conductors pass