chant vs religious song

chant and religious song both are nouns.

Word	Noun	Adjective	Verb	Adverb
chant	Yes	No	Yes	No
religious song	Yes	No	No	No

As nouns, religious song is a hypernym of chant; that is, religious song is a word with a broader meaning than chant:

chant: a repetitive song in which as many syllables as necessary are assigned to a single tone
religious song: religious music for singing

chant (noun)	religious song (noun)
a repetitive song in which as many syllables as necessary are assigned to a single tone	religious music for singing

chant (verb)	religious song (verb)
recite with musical intonation; recite as a chant or a psalm
utter monotonously and repetitively and rhythmically