Source : Webster's Revised Unabridged Dictionary (1913)

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}.

Oratory \Or"a*to*ry\, n. [L. oratoria (sc. ars) the oratorical
   art.]
   The art of an orator; the art of public speaking in an
   eloquent or effective manner; the exercise of rhetorical
   skill in oral discourse; eloquence. ``The oratory of Greece
   and Rome.'' --Milton.

         When a world of men Could not prevail with all their
         oratory.                                 --Shak.

Source : WordNet®

oratory
     n : addressing an audience formally (usually a long and
         rhetorical address and often pompous); "he loved the
         sound of his own oratory"