Definitions of collection
a group of objects such as works of art or pieces of writing brought together in one place
He was a violent criminal who nonetheless had a big gun collection.
presenting a negotiable instrument, eg a cheque or draft, for payment, or converting accounts receivable into cash
The draft is sent for collection, known as a documentary collection.
the act or process of gathering things from different places and bringing them together
Adopting encryption can make the mass collection of personal data more difficult and expensive.