Aggregator
From ACT Wiki
1. Payment systems.
An aggregator is one of a number of online payment service providers (PSPs) that enable e-commerce merchants to accept payments on the merchant's own website.
Aggregators allow merchants to accept credit card and debit card transfers without having to set up a merchant account with each card association or bank.
Instead, the aggregator takes the payments from the different card associations and banks, remitting a total to the merchant, net of the aggregator's charges.
2.
More generally, any structure or intermediary that combines smaller individual transactions or amounts, into larger combined transactions or amounts.