There's typically a low wall, about hip-high, in front of the first row of the choir. Religious architecture typically has its own terminology, and Christian architecture in particular. So is there a special name for that wall? Or is it just "that wall that keeps the first row of ladies from being embarrassed?"
Alternately, is there a name for the low wall that's sometimes in front of the first row of the congregation?
The low wall that separates the first row of the choir from the chancel is called a "choir rail."
The low wall that goes in front of the first pew is called a "pew screen," and also a "modesty screen" or "frontal," as seen in this church furniture page (scroll down for pictures of sample pew screens).
And to round things out: The low wall that separates the chancel from the rest of the church is called an "altar rail" or "communion rail."
The "low wall" in front of the first row of seats is a pew front. One function it has, apart from appearance, is it often has the book rest (and sometimes kneeler) for the seats behind.
In some cases where there are no longer pews this may be retained or there might be a similar modern structure.
If I understand your question correctly, the ecclesiastical term you are looking for is a prayer-desk.
"The back of each preceding row serves the succeeding one as a prayer-desk; the first row has a projection built in front of it for the same purpose."
The prayer-desk serves as prie-dieu, a bench for holding choir books and a desk for placing the book or books that are being used at a particular religious function.
This particular image, although for an individual can illustrate what I mean.
The choir stalls of Bristol Cathedral has an excellent example of the prayer-desk.
In Catholic Churches the benches (wall) in front of the first pews are called a prie-dieu.
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