mid-15c., vestri, (early 14c. as a surname), "room or outbuilding attached to a church for the keeping of clerical vestments and other church property," probably via Anglo-French *vesterie, from Old French vestiaire "room for vestments, dressing room" (12c.), from Latin vestarium "wardrobe," noun use of neuter of vestiarius (adj.) "of clothes," from vestis "garment" (from extended form of PIE root *eu- "to dress."). The earlier form in English was vestiarie (c. 1200).

The vestry also often served as meeting room for transaction of parish business or local government, and the word was retained in non-liturgical churches as the name of a separate room used for Sunday school, prayer meetings, etc.; hence also the transferred secular use in reference to a meeting or board of local voters (as in vestryman, 1610s). Related: Vestral.