decomposition

noun

de·​com·​po·​si·​tion (ˌ)dē-ˌkäm-pə-ˈzish-ən 

: the act or process of decomposing : the state of being decomposed:

a

: the separation or resolution (as of a substance) into constituent parts or elements or into simpler compounds

decomposition of mercuric oxide into mercury and oxygen

b

: organic decay

the decomposition of a dead body