quadrilateral figures

Of quadrilateral figures ,

a square is that which is both equilateral and right-angled;

an oblong that which is right-angled but not equilateral;

a rhombus that which is equilateral but not right-angled;

and a rhomboid that which has its opposite sides and angles equal to one another but is neither equilateral nor right-angled.

And let quadrilaterals other than these be called trapezia.

—Euclid