The term a-OK has several connotations depending on where in the world the user is standing when using the term. Typically attributed to an "all is OK" or "all is fine" statement, the origin of the term is often in debate. Some claim that the American term a-OK was first used in World War II in radio transmissions to indicate that a particular message was received all OK or when signaling that troops were all OK. Others claim that the term was initiated by the U.S. National Aeronautics and Space Agency (NASA) during the GEMINI phase. When used in other areas of the world, a-OK is very derogatory slang and is very offensive to most people who it is directed towards.
When used in NASA radio transmissions, the a-OK is based on the ability of the A to be more clearly heard in a poor signal than the OK all by itself. Poor radio reception and weak signals were responsible for many military mistakes due to misunderstanding in the early days of World War II. Radio communication required the users to reinvent a type of language that could be easily understood even among the static-filled air waves that were so common. By adding a letter in front of a basic word such as a-OK instead of a simple OK, the transmissions could be better identified and clearly understood.
Different accents and languages often conflicted when sending or receiving radio messages on the battlefield. The term a-OK is often used when scuba diving to indicate that everything is going well. It is commonly displayed in a hand gesture by circling the thumb and forefinger and holding the rest of the fingers splayed open. This is done mostly because the thumbs-up signal that would commonly indicate that everything is fine actually means to surface when underwater. In the Mediterranean area, the a-OK term and signal is often taken as an insult and can actually mean anus in some areas while it is referred to as the number of Satan in others.
The hand signal for a-OK is often used in Central Europe to indicate intoxication. When used in this connotation, the nose of the sign giver is placed inside of the "o" created when making the a-OK sign, indicating someone is intoxicated. The same sign flashed by a Japanese person can mean that he or she has no money. In Turkish areas, the sign is a vulgar reference to male homosexuality. In most European countries and the United States, it usually means that everything is going well.