summation vs aggregation

summation and aggregation both are nouns.

Word	Noun	Adjective	Verb	Adverb
summation	Yes	No	No	No
aggregation	Yes	No	No	No

As nouns, aggregation is a hypernym of summation; that is, aggregation is a word with a broader meaning than summation:

Other hypernyms of summation include accumulation, assemblage, collection.

summation (noun)	aggregation (noun)
the arithmetic operation of summing; calculating the sum of two or more numbers	the act of gathering something together
a concluding summary (as in presenting a case before a law court)	several things grouped together or considered as a whole
the final aggregate
(physiology) the process whereby multiple stimuli can produce a response (in a muscle or nerve or other part) that one stimulus alone does not produce