citation vs excerption

citation and excerption both are nouns.

Word	Noun	Adjective	Verb	Adverb
citation	Yes	No	No	No
excerption	Yes	No	No	No

As nouns, excerption is a hypernym of citation; that is, excerption is a word with a broader meaning than citation:

Other hypernyms of citation include excerpt, extract, selection.

citation (noun)	excerption (noun)
an official award (as for bravery or service) usually given as formal public statement	The act of excerpting or selecting from a larger work.
a short note recognizing a source of information or of a quoted passage	a passage selected from a larger work
a summons that commands the appearance of a party at a proceeding
a passage or expression that is quoted or cited
(law) the act of citing (as of spoken words or written passages or legal precedents etc.)