phase change vs thawing

phase change and thawing both are nouns.

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

As nouns, thawing is a hyponym of phase change; that is, thawing is a word with a more specific, narrower meaning than phase change:

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

Other hyponyms of phase change include freeze, freezing, liquefaction, melt, melting, thaw, evaporation, vapor, vaporisation, vaporization, vapour.

phase change (noun)	thawing (noun)
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