thaw vs phase change

thaw and phase change both are nouns.

Word	Noun	Adjective	Verb	Adverb
thaw	Yes	No	Yes	No
phase change	Yes	No	No	No

As nouns, phase change is a hypernym of thaw; that is, phase change is a word with a broader meaning than thaw:

thaw: the process whereby heat changes something from a solid to a liquid
phase change: a change from one state (solid or liquid or gas) to another without a change in chemical composition

Other hypernyms of thaw include heating, warming, phase transition, physical change, state change.

thaw (noun)	phase change (noun)
a relaxation or slackening of tensions or reserve; becoming less hostile	a change from one state (solid or liquid or gas) to another without a change in chemical composition
warm weather following a freeze; snow and ice melt
the process whereby heat changes something from a solid to a liquid

thaw (verb)	phase change (verb)
become or cause to become soft or liquid