Source : Webster's Revised Unabridged Dictionary (1913)

Ambrosian \Am*bro"sian\, a.
   Of or pertaining to St. Ambrose; as, the Ambrosian office, or
   ritual, a formula of worship in the church of Milan,
   instituted by St. Ambrose.

   {Ambrosian chant}, the mode of signing or chanting introduced
      by St. Ambrose in the 4th century.

Chant \Chant\, n.[F. chant, fr. L. cantus singing, song, fr.
   canere to sing. See {Chant}, v. t.]
   1. Song; melody.

   2. (Mus.) A short and simple melody, divided into two parts
      by double bars, to which unmetrical psalms, etc., are sung
      or recited. It is the most ancient form of choral music.

   3. A psalm, etc., arranged for chanting.

   4. Twang; manner of speaking; a canting tone. [R.]

            His strange face, his strange chant.  --Macaulay.

   {Ambrosian chant}, See under {Ambrosian}.

   {Chant royal} [F.], in old French poetry, a poem containing
      five strophes of eleven lines each, and a concluding
      stanza. -- each of these six parts ending with a common
      refrain.

   {Gregorian chant}. See under {Gregorian}.