不ふ等とう辺へん四し辺へん形けい

noun

trapezium; trapezoid

A quadrilateral with no parallel sides. In Japanese geometry, this term specifically refers to a general quadrilateral without any parallel sides, distinguishing it from 台形 (trapezoid with one pair of parallel sides) and 平行四辺形 (parallelogram).

• 不ふ等とう辺へん四し辺へん形けいは、どの辺へんも平へい行こうでない四し角かっ形けいです。

  A trapezium is a quadrilateral with no parallel sides.