accumulation vs increment

accumulation and increment both are nouns.

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

As nouns, increment is a hypernym of accumulation; that is, increment is a word with a broader meaning than accumulation:

accumulation: an increase by natural growth or addition
increment: a process of becoming larger or longer or more numerous or more important

Other hypernyms of accumulation include growth, increase.

accumulation (noun)	increment (noun)
the act of accumulating	the amount by which something increases
several things grouped together or considered as a whole	a process of becoming larger or longer or more numerous or more important
(finance) profits that are not paid out as dividends but are added to the capital base of the corporation
an increase by natural growth or addition