BA1100N means: BA1100N and BA1100N with Sierra Tango rings. An inside joke within the U.S. Military. It can be spelled “Bee Ay eleven thousand November” or “Bee Ay 11 hundred November with a Sierra Tango Ring” It is either a balloon, or a balloon and string when it’s written down. It is used to remove a recruit. They are sent to do something which makes them stupid, wastes time and results in extra work for them. It can be considered insulting to send it to someone because they won’t find one and cannot return to you without one. It is most effective when the person being used knows you. (in Community Dictionary, added by Thalia Molina)