Odd question. Directions?

[Mudbill]

This might seem a bit random and unrelated, but I'd like to use it in a little project of mine. It's more English than anything technical. Does anyone know what you call the cardinal directions when not relating to a compass?

Basically, something to use for north, east, west, south opposed to diagonally.

Let me try to explain with this figure:



If the red lines are called diagonals, what are the blue ones called? Looking from above, both red and blue are horizontal, but only the red are diagonal. I don't know what the blue ones are called xP

I tried Googling it, but didn't find anything. Not too sure what to search for anyway, because it's not the opposite of diagonal, but it's related I guess.

PS: I'm looking for a common word for it. Width and height would be awkward and sides I feel doesn't relate to diagonal, but rather corner.