Source : Webster's Revised Unabridged Dictionary (1913)

Vestment \Vest"ment\, n. [OE. vestement, vestiment, OF.
   vestement, vestiment, F. v[^e]tement, fr. L. vestimentum, fr.
   vestire to clothe, fr. vestis a garment, clothing. See
   {Vest}.]
   A covering or garment; some part of clothing or dress;
   specifically (Eccl.), any priestly garment. ``Royal
   vestiment.'' --Chaucer. ``Priests in holy vestments.''
   --Shak.

         The sculptor could not give vestments suitable to the
         quality of the persons represented.      --Dryden.

Source : WordNet®

vestment
     n : gown (especially ceremonial garments) worn by the clergy