Cops being referred to as “12” is a slang term with several competing theories, and there isn’t a universally agreed origin. Here are the most commonly discussed explanations:
- Radio code origin (10-12): A popular theory is that “12” derives from the police radio code 10-12, which historically signaled that visitors are present or that civilians are nearby. Over time, people shortened or repurposed this as a shorthand reference to police presence in an area. This is the explanation you’ll often see in popular articles and discussions.
- Adam-12 show influence: Another widely cited origin is the 1968–1974 TV show Adam-12 about two Los Angeles police officers, sometimes connecting the “12” to the show’s title and the unit designation “1-Adam-12.” Pop culture often shapes slang in ways that stick, similar to how “5-0” comes from Hawaii Five-0.
- Abbreviations related to ACAB slang: There’s also a theory tied to the acronym ACAB (All Cops Are Bastards). Some mention 1312 as a numeric stand-in, with 1=A, 3=C, 2=B, and then shortening to 12 in casual speech. This is more of a modern meme-like interpretation and varies in credibility by context.
- Other “unit or presence” interpretations: In some locales, people speculate that “12” could reference a specific unit number, badge, or personal identifier. These explanations tend to be less robust historically and are more anecdotal.
Practical takeaway:
- If you hear “12” in conversation or online, it’s typically used to indicate police presence or to warn others about cops being nearby. The exact origin is uncertain, but the radio-code and Adam-12 explanations are the most commonly cited foundations in discussions and popular media.
If you’d like, I can tailor this to a specific country or time period (for example, U.S. police slang vs. other regions) and pull more targeted sources.
