- Quadrilateral - A plane four-sided figure, having two sides parallel to
each other. - A bone of the carpus at the base of the second
metacarpal, or index finger. - Having the form of a trapezoid; trapezoidal; as, the
trapezoid ligament which connects the coracoid process and the
clavicle. - Of or pertaining to the trapezoid ligament; as, the
trapezoid line.