I’ve heard of cop being short for copper, which was the material used for the shields of beat cops. Other more valuable material being used for detectives etc…
The old TV show, Hawaii 5-0. The name was simply made up to sound “cool” for TV; there was never a “5-0” in Hawaii, or in any other state, for that matter.
Lesse, thirdy days hath Septober, April, June, and No Vember. (It’s true, there’s hardly any vember at all that has 30 days.) So, that doesn’t explain it.
I dunno. Possibly it’s off by the day that Joshua stopped the sun (at the bottle of Geritol.)
(BTW, on the TV show 5-O was a state police unit investigating, “organized crime, murder, assassination attempts, foreign agents, felonies of every type.” Before the series was aired, few knew that Hawaii was such a center of international espionage and miscellaneous wrongdoing. )
I read an interesting fictional term for police officers, in the three Jana Brill/Mama Maxwell sci-fi novels written by Lee Killough.
Police were often referred to as leos, or lions. Leo was “Law Enforcement Officer.” When you wanted to be derogatory to police you would say “Meow!” or “Here, kitty kitty.”