tail end in WordNet English dictionary

1. the fleshy part of the human body that you sit on
   "he deserves a good kick in the butt"; "are you going to sit on your fanny and do nothing?"
   buttocks  nates  arse  butt  backside  bum  buns  can  fundament  hindquarters  hind end  keister  posterior  prat  rear  rear end  rump  stern  seat  tail  tail end  tooshie  tush  bottom  behind  derriere  fanny  ass 
   
2. the time of the last part of something
   "the fag end of this crisis-ridden century"; "the tail of the storm"
   fag end  tail  tail end 
   
3. any projection that resembles the tail of an animal
   tail  tail end 
   

tail end in English Wiktionary