Definition
A fictitious proword used to end a conversation over push-to-talk radio.
How People Actually Use It
A conflicting term introduced by Hollywood and Military wannabes. In mediocre movies, the phrase is said to acknowledge a response on the radio. In actuality, "Over" means that you have heard the message and expect a reply while "Out" means that you have heard the message but you are ending the conversation.
"Soldier 1 : "Eh Sergeant, didn't that Corporal fail his radio test?" Soldier 2 : "That Chuck Norris addict said 'Over and Out' like the Holly-fucking-wood movie!""
Source: Urban Dictionary