decay vs decomposition

decay and decomposition both are nouns.

Word	Noun	Adjective	Verb	Adverb
decay	Yes	No	Yes	No
decomposition	Yes	No	No	No

As nouns, decay and decomposition are synonyms defined as:

As nouns, decomposition is a hyponym of decay; that is, decomposition is a word with a more specific, narrower meaning than decay:

decay: the process of gradually becoming inferior
decomposition: (biology) the process of decay caused by bacterial or fungal action

As nouns, decomposition is a hyponym of decay; that is, decomposition is a word with a more specific, narrower meaning than decay:

Other hyponyms of decay include putrefaction, rot, disintegration, deterioration, impairment, rancidity.

decay (noun)	decomposition (noun)
the organic phenomenon of rotting	the analysis of a vector field
a gradual decrease; as of stored charge or current	the organic phenomenon of rotting
the process of gradually becoming inferior	(biology) the process of decay caused by bacterial or fungal action
the spontaneous disintegration of a radioactive substance along with the emission of ionizing radiation	(chemistry) separation of a substance into two or more substances that may differ from each other and from the original substance
an inferior state resulting from the process of decaying	in a decomposed state

decay (verb)	decomposition (verb)
fall into decay or ruin
lose a stored charge, magnetic flux, or current
undergo decay or decomposition