aggregation

yhdistelmä, kokouma

koostaminen, yhdistäminen The act of collecting together (aggregating).
The state of being collected into a mass, assemblage, or sum (aggregated).
A collection of particulars; an aggregate.
puhekieltä summarizing multiple routes into one route.
puhekieltä the majority of the parasite population concentrated into a minority of the host population.
puhekieltä Kind of object composition which does not imply ownership.

The difference between an association and an aggregation is entirely conceptual and is focused strictly on semantics. (cite-book)