Using the matrix below for illustration, is there a term for the area(s) of the matrix which contains "B"? This would be the area of a matrix that is the largest possible square non-symmetircal submatrix that does not contain the diagonals of the main matrix.
$ \begin{pmatrix} A & A & B & B \\ A & A & B & B \\ B^T & B^T & C & C \\ B^T & B^T & C & C \end{pmatrix} $
I ask because, in my field, these three areas of a matrix each have important distinctions, and it's useful to compare these submatrices. I'm putting together some documentation and want to make sure that I'm using the right terminology!
Also, if there is a specific term for A and C, or for splitting a matrix into these four equal sized parts, then please go ahead and tell me.