the act of singing; "with a shout and a song they marched up to the gates"
a short musical composition with words; "a successful musical must have at least three good songs"
a distinctive or characteristic sound; "the song of bullets was in the air"; "the song of the wind"; "the wheels sang their song as the train rocketed ahead"
based on custom rather than documentation; "an unwritten law"; "rites...so ancient that they well might have had their unwritten origins in Aurignacian times"- J.L.T.C.Spence