rectangular coordinate system vs Cartesian coordinate system?

Question

Is there any difference between a rectangular coordinate system and a Cartesian coordinate system? Is one of them a subtype of the other?

My book mentions a rectangular Cartesian coordinate system. Isn't that a bit redundant?

Answer 1

It can be useful to have the two coordinate axes meet at an angle other than $90^\circ$. Rectangular Cartesian system means that the angle is $90^\circ$.

Answer 2

A Cartesian system of coordinates is a rectangular system of coordinates which has the same length for 1 unit for the X and Y axis.