roger /rɒdʒ.ə r / /rɑ.dʒɚ/ exclamation used in radio communications to mean that a message has been received and understood "You are clear to land." "Roger, I'm coming in to land now."

While in the current spelling alphabet (NATO), R is now Romeo, Roger has remained the response meaning "received" in radio voice procedure. In the US military, it is common to reply to another's assertion with "Roger that", meaning: "I agree". https://www.theguardian.com/notesandqueries/query/0,,-189587,00.html