song vs lament

song and lament both are nouns.

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

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

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

song (noun)	lament (noun)
the act of singing	a mournful poem; a lament for the dead
a short musical composition with words	a song or hymn of mourning composed or performed as a memorial to a dead person
the characteristic sound produced by a bird	a cry of sorrow and grief
a distinctive or characteristic sound
a very small sum

song (verb)	lament (verb)
	regret strongly
	express grief verbally