Definitions of tune:

• noun:   the adjustment of a radio receiver or other circuit to a required frequency
• noun:   the property of producing accurately a note of a given pitch

  Example: "He cannot sing in tune"

• noun:   a succession of notes forming a distinctive sequence
• verb:   of musical instruments

  Example: "My piano needs to be tuned"

• verb:   adjust for (better) functioning

  Example: "Tune the engine"

• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #10831)