break down in WordNet English dictionary

1. make a mathematical, chemical, or grammatical analysis of; break down into components or essential features
   "analyze a specimen"; "analyze a sentence"; "analyze a chemical compound"
   analyze  analyse  break down  dissect  take apart 
   
2. stop operating or functioning
   "The engine finally went"; "The car died on the road"; "The bus we travelled in broke down on the way to town"; "The coffee maker broke"; "The engine failed on the way to town"; "her eyesight went after the accident"
   fail  go bad  give way  die  give out  conk out  go  break  break down 
   
3. collapse due to fatigue, an illness, or a sudden attack
   break down  collapse 
   
4. separate (substances) into constituent elements or parts
   decompose  break up  break down 
   
5. make ineffective
   "Martin Luther King tried to break down racial discrimination"
   break down  crush 
   
6. cause to fall or collapse
   break down 
   
7. lose control of one's emotions
   "When she heard that she had not passed the exam, she lost it completely"; "When her baby died, she snapped"
   break down  lose it  snap 
   
8. fall apart
   "the building crumbled after the explosion"; "Negotiations broke down"
   crumble  crumple  tumble  break down  collapse 
   

break down in English Wiktionary