- quadrilateral, four-sided - having four sides
Antonyms: bilateral, two-sided (indirect, via unilateral, multilateral)
Antonyms: unilateral, one-sided (indirect, via multilateral, bilateral)
- quadrilateral, quadrangle, tetragon - a four-sided polygon
--1 is a kind of polygon, polygonal shape
--1 has particulars: parallelogram; trapezium; trapezoid