break down break down /breɪk daʊn/

verb

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