# Definition:Cartesian 3-Space/Coordinate Planes

## Definition

Consider the Cartesian $3$-space defined by $3$ distinct perpendicular planes through the origin $O$.

These $3$ planes are known as the coordinate planes of the Cartesian $3$-space.

### $x$-$y$ Plane

The $x$-$y$ plane is the Cartesian plane embedded in Cartesian $3$-space which contains the $x$-axis and the $y$-axis.

It consists of all the points in $S$ such that $z = 0$.

### $y$-$z$ Plane

The $y$-$z$ plane is the Cartesian plane embedded in Cartesian $3$-space which contains the $y$-axis and the $z$-axis.

It consists of all the points in $S$ such that $x = 0$.

### $x$-$z$ Plane

The $x$-$z$ plane is the Cartesian plane embedded in Cartesian $3$-space which contains the $x$-axis and the $z$-axis.

It consists of all the points in $S$ such that $x = 0$.