Y it is called a boxing ring when this arena is a square?

Question

Y it is called a boxing ring when this arena is a square?

Answer 1

The name ring is an atavism from when contests were fought in a roughly drawn circle on the ground. The name ring continued with the Jack Broughton rules in 1743, which specifed a small circle in the centre of the fight area where the boxers met at the start of each round. The first square ring was introduced by the Pugilistic Society in 1838. That ring was specified as 24 feet square and bound by two ropes. For these and other reasons, the boxing ring is commonly humorously referred to as the "square circle."

Answer 2

Boxing used to be fought in a ring drawn on the ground. As rules were codified and held indoors, a ring shape was used, mostly because it's easier to demarcate the area with ropes using a square.

Nowadays, some MMA organizations use a circular cage to hold the combatants.