decrease in WordNet English dictionary

1. the act of decreasing or reducing something
   decrease  diminution  reduction  step-down 
   
2. the amount by which something decreases
   decrease  decrement 
   
3. a change downward
   "there was a decrease in his temperature as the fever subsided"; "there was a sharp drop-off in sales"
   decrease  lessening  drop-off 
   
4. a process of becoming smaller or shorter
   decrease  decrement 
   

1. decrease in size, extent, or range
   "The amount of homework decreased towards the end of the semester"; "The cabin pressure fell dramatically"; "her weight fell to under a hundred pounds"; "his voice fell to a whisper"
   decrease  diminish  lessen  fall 
   
2. make smaller
   "He decreased his staff"
   decrease  lessen  minify