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.
Triangular Ruler was approved as part of Unicode 6.0 in 2010 and added to Emoji 1.0 in 2015.