hardening vs annealing

hardening and annealing both are nouns.

Word	Noun	Adjective	Verb	Adverb
hardening	Yes	No	No	No
annealing	Yes	No	No	No

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

hardening: the act of making something harder (firmer or tighter or more compact)
annealing: hardening something by heat treatment

Other hyponyms of hardening include tempering.

hardening (noun)	annealing (noun)
the act of making something harder (firmer or tighter or more compact)	hardening something by heat treatment
the process of becoming hard or solid by cooling or drying or crystallization
abnormal hardening or thickening of tissue