antechoir

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A place in front of the choir reserved for the clergy and choir members.

from The Century Dictionary.

• noun In architecture, a space, more or less inclosed, in front of the choir of a church; a portion of the nave adjoining the choir-screen and separated from the rest of the nave by a railing. Also called fore-choir.

from the GNU version of the Collaborative International Dictionary of English.

• noun A space inclosed or reserved at the entrance to the choir, for the clergy and choristers.
• noun Where a choir is divided, as in some Spanish churches, that division of it which is the farther from the sanctuary.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun the part of a church in front of the choir, often reserved for the clergy