10-4 means "OK," "understood," and "affirmative." Commonly known as CB radio lingo, originating from the need for brevity in radio transmission.me--"Is anyone there?" respondent--" 10-4"(to indicate presence). me--"Let's roll." respondent--"10-4"(to indicate agreement).最初是为了无线电发报时做的简写，意思就是：十分肯定，明白希望对你有帮助~
