abecedarius vs poem

abecedarius and poem both are nouns.

Word	Noun	Adjective	Verb	Adverb
abecedarius	Yes	No	No	No
poem	Yes	No	No	No

As nouns, poem is a hypernym of abecedarius; that is, poem is a word with a broader meaning than abecedarius:

abecedarius: a poem having lines beginning with letters of the alphabet in regular order
poem: a composition written in metrical feet forming rhythmical lines

Other hypernyms of abecedarius include verse form.

abecedarius (noun)	poem (noun)
a poem having lines beginning with letters of the alphabet in regular order	a composition written in metrical feet forming rhythmical lines