It means brick between post (French). That’s the wall construction style I was telling you about in the post about our lunch at The Cabin. Here’s the picture again so you can see the wall construction method I’m talking about.
Here’s two pictures of the same method as used at St. Joseph Plantation in Vacherie, LA. These examples were in the stairwell up to the third floor. Visitors are not allowed up there but we were told that it is one continuous room across the entire house.