What is "choir wall"

Choir \Choir\, n. [OE. quer, OF. cuer, F. ch[oe]ur, fr. L. chorus a choral dance, chorus, choir, fr. Gr. ?, orig. dancing place; prob. akin to ? inclosure, L. hortus garden, and E. yard. See Chorus.]

1. A band or organized company of singers, especially in church service. [Formerly written also quire.]

2. That part of a church appropriated to the singers.

3. (Arch.) The chancel.

   Choir organ (Mus.), one of the three or five distinct organs included in the full organ, each separable from the rest, but all controlled by one performer; a portion of the full organ, complete in itself, and more practicable for ordinary service and in the accompanying of the vocal choir.

   Choir screen, Choir wall (Arch.), a screen or low wall separating the choir from the aisles.

   Choir service, the service of singing performed by the choir.
   --T. Warton.