religious song vs chant

religious song and chant both are nouns.

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

As nouns, chant is a hyponym of religious song; that is, chant is a word with a more specific, narrower meaning than religious song:

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

Other hyponyms of religious song include Negro spiritual, spiritual, carol, Christmas carol, anthem, hymn.

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

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