Merriam-Webster Collegiate Dictionary - offertory

 noun  (plural -ries)  Etymology: Middle English offertorie, from Medieval Latin offertorium, from Late Latin offerre  Date: 14th century  1. often capitalized  a. the eucharistic offering of bread and wine to God before they are consecrated  b. a verse from a Psalm said or sung at the beginning of the ~  2.  a. the period of collection and presentation of the offerings of the congregation at public worship  b. a musical composition played or sung during an ~