The Chinese name for the Pythagorean Theorem is 勾股定理
Take a right angle triangle ABC
Let side AB be the shortest side.
Let AC be the second shortest side.
BC is therefore the longest side and the hypotenuse.
In Chinese the side AB is called 勾, the side AC is called 股 and the side BC is called 弦.
In English the two shorter sides are called “legs”.
Why were the two “legs” called 勾 and 股 ?
It makes sense that the hypotenuse is called 弦 as the triangle is usually drawn such that the hypotenuse is diagonal.