The best replacement for quadrangle is quadrilateral.

The best alternatives to quadrangle are rated as following:
★★★★★  quadrilateral
★★★  rectangle
★  trapezoid

Your alternative for quadrangle is not listed? Suggest!
Speaking about quadrangle, one probably shouldn't forget about right angle.

Other search terms related to quadrangle and their ratings are:
★★★★★ right angle
You have in mind a companion for quadrangle and it is not yet here? Propose!



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quadrangle
quadrilateral
rectangle