Why are they called "Gentlemen's" clubs?????

gen·tle·man
Function: noun
Usage: often attributive
Etymology: Middle English gentilman

(1) : a man who combines gentle birth or rank with chivalrous qualities (2) : a man whose conduct conforms to a high standard of propriety or correct behavior

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Above is the definition of the word gentleman. i think that it is pretty straightforward, which is why i am baffled by strip clubs that call refer to themselves as a "Gentlemen's Club". There is absolutely nothing genteel or refined about what happens at a strip club.