accumulation vs accretion

accumulation and accretion both are nouns.

Word	Noun	Adjective	Verb	Adverb
accumulation	Yes	No	No	No
accretion	Yes	No	No	No

As nouns, accumulation and accretion are synonyms defined as:

accumulation (noun)	accretion (noun)
the act of accumulating	(law) an increase in a beneficiary's share in an estate (as when a co-beneficiary dies or fails to meet some condition or rejects the inheritance)
several things grouped together or considered as a whole	an increase by natural growth or addition
(finance) profits that are not paid out as dividends but are added to the capital base of the corporation	(geology) an increase in land resulting from alluvial deposits or waterborne sediment
an increase by natural growth or addition	(biology) growth by addition as by the adhesion of parts or particles
	(astronomy) the formation of a celestial object by the effect of gravity pulling together surrounding objects and gases
	something contributing to growth or increase