(automotive) a triangle made of usually red reflective material, used to warn other road users of a broken-down vehicle

plural of triangulation pillar

(UK) A concrete pillar used by the Ordnance Survey as a point for taking theodolite measurements, used in determining the exact shape of the country in a mid-20th-century retriangulation project.

The quality of being trigger-happy.

A triad in which one person is in a polyamorous relationship with two other people who are not in a relationship with each other.

A drumhead court-martial.

(law) a court of first instance.

A trifle made with chocolate and cherries, like a Black Forest gâteau.

(geometry) Any of a number of triangles described in Morley's trisector theorem, especially the equilateral triangle formed from the points of intersection of adjacent angle trisectors of a given triangle.

Three traditional components of a nuclear weapons arsenal: strategic bombers, intercontinental ballistic missiles, and submarine-launched ballistic missiles.