Am I correct in thinking that a 'trapezoid' is known as a 'trapezium' in British English?
It's too bad the writers of Big Bang Theory don't use Duolingo. Sheldon and Stephen Hawking could have had a hilarious argument over the correct definition of trapezoid.
I thought מרובע meant square. Does Hebrew not have different words for square and quadrilateral?
Yes, ריבוע is a square and מרובע is a quadrilateral or a quadrangle by Duolingo.