chrestomathy vs excerption

chrestomathy and excerption both are nouns.

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

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

chrestomathy: a selection of passages from different authors that is compiled as an aid in learning a language
excerption: a passage selected from a larger work

Other hypernyms of chrestomathy include excerpt, extract, selection.

chrestomathy (noun)	excerption (noun)
a selection of passages from different authors that is compiled as an aid in learning a language	The act of excerpting or selecting from a larger work.
	a passage selected from a larger work