What is the correct English name of these lines?

Hello.

I'm looking for the English name of these two lines in a two dimensional plane:

• they go through the origin
• they make angles of 45° and 135° with the $x$-axis, dividing the plane in two parts

From my native language, they would translate to "first bissector" and "second bissector" or "first diagonal" and "second diagonal", but I could not find any reference to such names.

Solution 1:

"The diagonal" (is $\{y=x\}$) and "the anti-diagonal" (is $\{y=-x\}$).

Solution 2:

These are lines where, if $\theta$ is the angle made with the positive $x$-axis, we have $ |\tan x| = 1 $. Thus, these are lines with slope $\pm1$.

Solution 3:

If there was a specific English name, it isn't well known.