Definitions of cancel:

• noun:   a notation cancelling a previous sharp or flat
• verb:   declare null and void; make ineffective

  Example: "Cancel the election results"

• verb:   postpone indefinitely or annul something that was scheduled

  Example: "Cancel the dinner party"

• verb:   make up for
• verb:   of cheques or tickets
• verb:   remove or make invisible
• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #7694)