offertory (n.) Look up offertory at Dictionary.com
"the part of a Mass at which offerings are made," late 14c., from Medieval Latin offertorium "place where offerings are brought," from Vulgar Latin offertus, corresponding to Latin oblatus, past participle of offerre (see offer (v.)). Meaning "part of a religious service" is first recorded 1530s; sense of "collection of money" is from 1862.