cancel in WordNet English dictionary

1. postpone indefinitely or annul something that was scheduled
   "Call off the engagement"; "cancel the dinner party"; "we had to scrub our vacation plans"; "scratch that meeting--the chair is ill"
   cancel  call off  scratch  scrub 
   
2. make invalid for use
   "cancel cheques or tickets"
   cancel  invalidate 
   
3. remove or make invisible
   "Please delete my name from your list"
   delete  cancel 
   
4. declare null and void; make ineffective
   "Cancel the election results"; "strike down a law"
   cancel  strike down 
   
5. make up for
   "His skills offset his opponent's superior strength"
   cancel  offset  set off 
   

1. a notation cancelling a previous sharp or flat
   natural  cancel