enlargement vs step-up

enlargement and step-up both are nouns.

Word	Noun	Adjective	Verb	Adverb
enlargement	Yes	No	No	No
step-up	Yes	No	No	No

As nouns, step-up is a hypernym of enlargement; that is, step-up is a word with a broader meaning than enlargement:

enlargement: the act of increasing (something) in size or volume or quantity or scope
step-up: the act of increasing something

Other hypernyms of enlargement include increase.

enlargement (noun)	step-up (noun)
the act of increasing (something) in size or volume or quantity or scope	the act of increasing something
a photographic print that has been enlarged
a discussion that provides additional information
the state of being enlarged