Homonym: 10/4 (Acknowledgment)
"10/4" is a term commonly used in radio communication, particularly in the context of the Citizen Band (CB) radio and other two-way radio systems. It is part of the ten-codes, a set of brevity codes that help convey messages quickly and clearly. Specifically, "10/4" means "message received" or "acknowledged," indicating that the listener understands the information being communicated.
The use of "10/4" became popular in the 1970s, especially among truck drivers and emergency services. It has since entered popular culture, often associated with the American trucking industry and depicted in movies and television shows. The phrase is sometimes used informally in everyday conversation to confirm understanding.