diminution vs erosion

diminution and erosion both are nouns.

Word	Noun	Adjective	Verb	Adverb
diminution	Yes	No	No	No
erosion	Yes	No	No	No

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

diminution (noun)	erosion (noun)
the act of decreasing or reducing something	(geology) the mechanical process of wearing or grinding something down (as by particles washing over it), also figuratively
the statement of a theme in notes of lesser duration (usually half the length of the original)	erosion by chemical action
change toward something smaller or lower	a gradual decline of something
	condition in which the earth's surface is worn away by the action of water and wind