indentation vs corrosion

indentation and corrosion both are nouns.

Word	Noun	Adjective	Verb	Adverb
indentation	Yes	No	No	No
corrosion	Yes	No	No	No

As nouns, corrosion is a hypernym of indentation; that is, corrosion is a word with a broader meaning than indentation:

indentation: the formation of small pits in a surface as a consequence of corrosion
corrosion: erosion by chemical action

Other hypernyms of indentation include corroding, erosion.

indentation (noun)	corrosion (noun)
the act of cutting into an edge with toothlike notches or angular incisions	erosion by chemical action
the space left between the margin and the start of an indented line	a state of deterioration in metals caused by oxidation or chemical action
the formation of small pits in a surface as a consequence of corrosion
a concave cut into a surface or edge (as in a coastline)