The Collaborative International Dictionary
oratorians
Oratory \Or"a*to*ry\, n.; pl. Oratories. [OE. oratorie, fr. L. oratorium, fr. oratorius of praying, of an orator: cf. F. oratoire. See Orator, Oral, and cf. Oratorio.] A place of orisons, or prayer; especially, a chapel or small room set apart for private devotions.
An oratory [temple] . . . in worship of Dian.
--Chaucer.
Do not omit thy prayers for want of a good oratory, or
place to pray in.
--Jer. Taylor.
Fathers of the Oratory (R. C. Ch.), a society of priests founded by St. Philip Neri, living in community, and not bound by a special vow. The members are called also oratorians.
Wiktionary
oratorians
n. (plural of oratorian English)