accretion vs accumulation

accretion and accumulation both are nouns.

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

As nouns, accretion and accumulation are synonyms defined as:

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