oratory

Etymology 1

From Middle English oratorie, from Anglo-Norman oratorie, Middle French oratoire, and their source, Late Latin ōrātōrium. Doublet of oratorio.

noun

1. A private chapel or prayer room.
   I will retire to my oratory, and pray to the blessed Virgin to inspire you with her holy counsels […]. 1764, Horace Walpole, “chapter II”, in The Castle of Otranto
2. A Roman Catholic chapel; a building for public or private worship that is not a parish church.
   By public oratories are meant those attached to monasteries, convents, seminaries, etc., having a public entrance by which the faithful have access to them. 1876, Michael Comerford, The Book of Holy Indulgences […], page 29
3. (specifically) A Catholic church belonging to the Oratory of Saint Philip Neri.
   They had been given the old Oscott College premises as a temporary home, but were content there until Oratories could be established in the cities. St Philip Neri had specifically intended that the Oratory should be a city-based form of communal and missionary life. 2006, Judith F. Champ, William Bernard Ullathorne, 1806–1889: A Different Kind of Monk, page 168

Etymology 2

Borrowed from Latin ōrātōria, from the feminine of ōrātōrius (“oratorial”).

noun

1. The art of public speaking, especially in a formal, expressive, or forceful manner.
2. Eloquence; the quality of artistry and persuasiveness in speech or writing.