A triangle or set square, as used by engineers or architects to draw straight lines at angles. Variously depicted as a metal, wood, or plastic right triangle with length markings, its hypotenuse to the right.

Commonly applied to a range of disciplines, including art, design, building, architecture, and STEM (science, technology, engineering, and mathematics). May also represent various concepts of angles and measurement.

Geodriehoek is goedgekeurd als onderdeel van Unicode 6.0 in 2010 en toegevoegd aan Emoji 1.0 in 2015.