state change vs thawing

state change and thawing both are nouns.

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

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

state 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 state change include freeze, freezing, liquefaction, melt, melting, thaw, evaporation, vapor, vaporisation, vaporization, vapour.

state 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