I am looking for the terms to use for particular types of diagonals in two dimensional matrices. I have heard the longest diagonal, from top-left element and in the direction down-right often called the "leading diagonal".
-What about the 'other' diagonal, from the top right going down-left? Does it have a common name?
-Any general name to use for any diagonal going top-left to bottom-right direction, not necessarily just the longest one(s)? I am searching for a term to distinguish between these types of diagonals and the ones in the 'other' direction. Preferably the term should not be restricted to square matrices.