Interesting question, Frank.
The term has been around since the 1860’s to describe a short panted suit for boys, as only men wore long pants with a suit. Until a boy reached manhood (age 13) he was not allowed to wear long pants with a suit. Women were not allowed to wear suits at all. When women had enough of that nonsense, they started wearing semi looking suits, and the term somehow switched over to describe that style of clothing. It was an exciting time. Perhaps geoff could better describe it through interpretive dance.