noun

• (music) A musical composition with lyrics for voice or voices, performed by singing.
  "Thomas listened to his favorite song on the radio yesterday."
• (by extension) Any musical composition.
• (ornithology) The distinctive sound that a male bird utters to attract a mate or to protect his territory; contrasts with call; also, similar vocalisations made by female birds.
• (obsolete) An object of derision; a laughing stock.
  "And now am I their song, yea, I am their byword."

name

• (historical) A former dynasty in China, reigning from the end of the Five Dynasties and Ten Kingdoms to the beginning of the Yuan.
  "A 1,000-year-old bowl from China's Song Dynasty sold at auction for $37.7 million on Tuesday, breaking the record for Chinese porcelain, auction house Sotheby?s said. The small piece -- which dates from 960-1127 -- broke the previous record of $36.05 million set in 2014 for a Ming Dynasty wine cup which was sold to a Shanghai tycoon."
• (historical) A former empire in China, occupying the eastern half of modern China.
• (historical) The era of Chinese history during which the dynasty reigned.