Hotkey: R, Shift+ R

Default UI Menu: Modes/Coord System/Relative Coords

Ribbon UI Menu:

Cartesian (X, Y) coordinates relative to a specified origin.

Tip: If you precede a coordinate with an @ sign it will be interpreted as a relative coordinate.

The relative origin can move as you work, relocating to each selected point, or it can remain fixed. The relative origin is controlled by the Fixed relative origin box on the Advanced Preferences page of the Program Setup. The relative origin is marked by a red square. You can use Relocate Origin (Shift+L) at any time to move it.

Relative Origin not fixed

Relative Origin fixed

You can enter relative X and Y values in the Coordinate Fields. Note the +/- symbols, indicating that the distance is not absolute.