requiem vs song

requiem and song both are nouns.

Word	Noun	Adjective	Verb	Adverb
requiem	Yes	No	No	No
song	Yes	No	No	No

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

requiem: a song or hymn of mourning composed or performed as a memorial to a dead person
song: a short musical composition with words

Other hypernyms of requiem include vocal.

requiem (noun)	song (noun)
a song or hymn of mourning composed or performed as a memorial to a dead person	the act of singing
	a short musical composition with words
	the characteristic sound produced by a bird
	a distinctive or characteristic sound
	a very small sum