The Collaborative International Dictionary
Triquadrantal
Triquadrantal \Tri`quad*ran"tal\, a. [Pref. tri- + quadrantal.] (Spherical Trig.) Having three quadrants; thus, a triquadrantal triangle is one whose three sides are quadrants, and whose three angles are consequently right angles.
Wiktionary
triquadrantal
a. (context geometry English) Having three quadrants.