song 
(sông, sŏng)
(sông, sŏng)n.
Idiom: 1. Music
a. A brief composition written or adapted for singing.
b. The act or art of singing: broke into song.
2. A distinctive or characteristic sound made by an animal, such as a bird or an insect.
3.
a. Poetry; verse.
b. A lyric poem or ballad.
for a song Informal
At a low price: bought the antique tray for a song.
[Middle English, from Old English sang; see sengwh- in the Appendix of Indo-European roots.]