Why Are Police Called The 5-0?

Cops. The fuzz. The heat. Pigs. The boys in blue. As you may already know, these are just some of the many nicknames — some slightly endearing, others downright derogatory — for police officers. Perhaps you've heard a few of them used on your favorite reality crime show like "Cops" or "Live P.D.," or uttered by a hardboiled detective against the moody backdrop of a film noir. Maybe you've even used a few of them yourself in real life. That being said, do you know where all those nicknames derive from?

While some police officer nicknames (like "po-po") originated in the streets, others were inspired by the screen. For instance, have you ever heard someone refer to the police as "5-O?" The term may not be as commonly used anymore, but it might sound especially familiar. Its roots can be traced back to 1968 with the don of a fictional police television show: "Hawaii Five-O."

Starring Jack Lord as Detective Lieutenant Steve Garrett, the original "Hawaii Five-O" ran for 12 action-packed seasons from 1968 to 1980 — while its successful 2010 reboot ran for a decade. Shot on location in sun-kissed Honolulu, the classic television show followed a fictional police task force known as, you guessed it, Hawaii Five-O. In case you're wondering what the show's title means, quite simply, it's a reference to Hawaii becoming the 50th state. But in reality, Hawaiian police never referred to themselves as "Hawaii-5-O," that was just a catchy show title invented by its creators. 

In addition to inspiring the famous catchphrase "Book 'em, Danno!" (a phrase Detective Garrett often delivered to his partner Danny "Danno" Williams on the show before making an arrest), "Hawaii Five-O" also popularized the police nickname, "5-O". When people want to let others know about a police presence nearby, they may say, "watch out for 5-O." 

Another theory behind the nickname's origin is that it derives from the 5.0-liter engine badges that appeared on unmarked Ford police cars during the 1980s. However, this theory isn't as widely accepted, and a quick Google search will prove that most sources support the television show's origin story.

"Hawaii Five-O" isn't the only television show in history to inspire a police nickname. The popular 1960s sitcom "The Andy Griffith Show," is the reason some police officers are called "Barneys." It's a reference to one of its most beloved characters, Deputy Barney Fife. "Smokey" is another law enforcement nickname inspired by pop culture, thanks to the famous cartoon character synonymous with forest fire prevention. This bit of trucker lingo became more widely known following the 1977 film, "Smokey and the Bandit," proving yet another example of pop culture's influence on police officer nicknames.

Those examples don't seem as ubiquitous as 5-O these days. However, with a combined 22 years on TV between the original "Hawaii 5-O" and the 21st-century reboot, it's no wonder the term 5-O became well-known slang to refer to the police.