Definition of orarium in US English:

orarium

noun

Christian Church
  • An ecclesiastical stole; (now) specifically the stole worn by a deacon in the Greek and Russian Orthodox Churches.

Origin

Early 18th century; earliest use found in Phillips's New World of Words. From post-classical Latin orarium a napkin, handkerchief (Vetus Latina), stole from classical Latin ōr-, ōs mouth, face + -ārium.