heating pad vs hot pad

heating pad and hot pad both are nouns.

Word	Noun	Adjective	Verb	Adverb
heating pad	Yes	No	No	No
hot pad	Yes	No	No	No

As nouns, heating pad and hot pad are synonyms defined as:

heating pad and hot pad: heater consisting of electrical heating elements contained in a flexible pad

heating pad (noun)	hot pad (noun)
heater consisting of electrical heating elements contained in a flexible pad	heater consisting of electrical heating elements contained in a flexible pad
	a pad for use under a hot dish to protect a table