Definitions of sing:

• verb:   to make melodious sounds

  Example: "The nightingale was singing"

• verb:   produce tones with the voice

  Example: "She was singing while she was cooking"

• verb:   deliver by singing

  Example: "Sing Christmas carols"

• verb:   make a whining, ringing, or whistling sound

  Example: "The kettle was singing"

• verb:   divulge confidential information or secrets
• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #12947)