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

The condition of being tetragonal.

In a tetragonal manner

Having four sides, like a tetragon. / (crystallography) Having two equal axes and one unequal, and all angles 90°.

plural of tetragon

(chiefly botany) tetragonal

(dated, mathematics) quadrature of the circle

(zoology) Any ammonite in the family Tetragonitidae.

(ichthyology) Any fish in the family Tetragonuridae, the squaretails.

plural of tetragonurid