What is the meaning of Offertory?

A prayer said or sung as an anthem while offerings of bread and wine are placed on the altar during the Roman Catholic Mass or the Anglican Communion service.

The part of the Eucharist service when offerings of bread and wine are placed on the altar and when any collection is taken; also, the money or other things collected.

A linen or silken cloth anciently used in various ceremonies connected with the administration of the Eucharist.

offertory

Source: wiktionary.org