(Church of England) an assistant to the churchwarden; collects offerings of money in the church WordNet 3.0 & Open English WordNet

A sidesperson, also known as a sidesman, usher, or assistant churchwarden, in Anglican churches is responsible for greeting members of the congregation, overseeing seating arrangements in church, making the congregation queue for communion at the altar in an orderly way, and for taking the collection. Wikipedia

An assistant to a churchwarden, one of whose duties is to collect offerings during a service. Wiktionary