Why are quatrains called quatrains?

The quatrains are also called "Jue". The combination of rhythm and abstinence is called "modern poetry" or "modern poetry"

There are only four quatrains, mostly prose, but also antithesis, or one or two sentences relative, or three or four sentences relative. Why is it called quatrains? According to Fan Yuan Deji's theory, cutting off half or four sentences in the middle (or before and after) of a metrical poem is an absolute "deletion".