What does "song" mean?

Additional senses

1. 2.More generally, any poetical strain; a poem. The bard that first adorned our native tongue Tuned to his British lyre this ancient song. Dryden.
2. 3.Poetical composition; poetry; verse. This subject for heroic song. Milton.
3. 4.An object of derision; a laughingstock. And now am I their song. yea, I am their byword. Job xxx.
4. 5.6. A trifle. "The soldier's pay is a song." Silliman. Old song, a trifle; nothing of value. "I do not intend to be thus put off with an old song." Dr. H. More. -- Song bird (Zoöl.), any singing bird; one of the Oscines. -- Song sparrow (Zoöl.), a very common North American sparrow (Melospiza fasciata, or M. melodia) noted for the sweetness of its song in early spring. Its breast is covered with dusky brown streaks which form a blotch in the center. -- Song thrush (Zoöl.), a common European thrush (Turdus musicus), noted for its melodius song; -- called also mavis, throsite, and thrasher.