What Does 10-4 Mean? Exploring the Origins and Meaning of a Popular Slang Phrase

If you’ve ever spent time on a CB radio or other two-way communication device, then you’ve probably heard the phrase “10-4.” But what does 10-4 mean? Where did this phrase come from and why did it become such a popular slang term? In this article, we’ll take a look at the history and meaning of 10-4, as well as its various permutations.

The Origin of 10-4

10-4 is believed to have originated in the early 20th century, when police and other law enforcement agencies began to use two-way radios. The phrase “10-4” was used to indicate that the receiving officer had heard and understood a message. It quickly became popular and was soon adopted by many radio operators outside of law enforcement, including truck drivers, railroad employees, and CB radio users.

A Mutually-Understood Meaning

Over the course of many decades, the phrase “10-4” has come to be used as an affirmative response to a question or statement. It might be used to confirm an understanding, to express agreement, or simply to indicate that the speaker has heard another person. It is typically used in an informal context, such as in conversation between friends or colleagues, and can be modified in various ways in order to convey additional information or to add emphasis.

The Many Variations of “10-4”

The term “10-4” can be modified in numerous ways in order to add context and meaning. Some popular permutations of 10-4 include 10-4 Good Buddy, 10-4 Roger That, 10-4 Copy That, 10-4 Over and Out, and 10-4 Roger Wilco. Each of these variations carries an additional implied meaning, whether it’s expressing agreement with someone’s point of view or acknowledging that a message has been understood.

10-4 is a phrase that has been used by police officers, truck drivers, CB radio users, and countless others for decades. Its roots lie in law enforcement, where it was used as a confirmation that a message had been understood. Today, it’s used as an informal way of expressing agreement or understanding in personal or professional conversations.