I've heard quite a few times the term "five O" (eg in the US TV show "the Wire").
It seems to mean "police" (inferred from the context), and I'm curious to know where the expression comes from, and if it has a broader meaning than just "police".
It comes from the American police show Hawaii Five-O; "five-o" has since become a slang term for police. In the show, "Five-O" is just a police unit, but the name itself doesn't really mean anything other than a designation (I believe the writers named it "Five-O" in homage to Hawaii, the 50th US state and the location of the show).
From the old cop show Hawaii Five-O, sadly enough (which in turn got its name from the fact that Hawaii was the 50th state to join the union).
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