tetragon

/ˈtɛ.tɹə.ɡɒn/

ot noun

Quadrilateral.
An aspect of two planets with regard to the Earth when they are distant from each other ninety degrees, or a quarter-circle.

Manbalar: Wiktionary (Free Dictionary API orqali), Datamuse, Tatoeba (CC BY 2.0 FR), MyMemory.