ˌSing a ˌsong of ˈsixpence BrE AmE
a ↑ nursery rhyme (=an old song or poem for young children) which starts: Sing a song of sixpence,/A pocket full of rye;/Four-and-twenty blackbirds/Baked in a pie./When the pie was opened,/The birds began to sing,/Wasn't that a dainty dish/To set before the King?