song

Concise Oxford English Dictionary © 2008 Oxford University Press:
song/sɒŋ/

▶noun

• 1 a short poem or other set of words set to music.

  ■ singing or vocal music.

  ■ a musical composition suggestive of a song.

• 2 the musical phrases uttered by some birds, whales, and insects, used chiefly for territorial defence or for attracting mates.

• 3 a poem, especially one in rhymed stanzas.

  ■ archaic poetry.

– phrases
for a song informal very cheaply.
on song Brit. informal performing well.
a song and dance informal, chiefly Brit. a fuss.

■ N. Amer. a long and pointless or evasive explanation.

– origin OE sang, of Gmc origin; rel. to sing.