Secret code words
Mayday, mayday, mayday! - This is a universal distress signal in a case of emergency. It's usually transmitted via radio.
"Pan-Pan" is used when there's a problem but the situation is not deemed serious enough and no lives are at risk, so using "Mayday" would be overkill.
You don't want your pilot to ever mention this number. The code 7500 means that the plane is being hijacked.
Code Adam -
This one is used in several public places, including malls, airports, museums, and hospitals. It means that a child has gone missing.
Code Oscar or Mr Mob -
Shouting "Man overboard!" is probably not the best option in a crowded vessel. Instead, "oscar, oscar, oscar" is used.
Code 10 - A "Code 10" can be issued by merchants if they suspect someone is committing credit card fraud.
1488 - Used by white supremacists around the world, if you see this number in an email address, a t-shirt, or a tattoo, you'll know the person has a Neo-nazi ideology.
London Underground cleaning codes - There's a specific code for each situation. These include, code 1 for blood, code 2 for urine/feces, and code 3 for vomit.
Code 18 - If another tech guy says you have a "Code 18," then this means the problem is 18 inches from the screen. Yes, you again!
Protein spill -
If you happen to throw up at Disneyland, employees will refer to the incident as a "Protein spill" or a "Code v."
Code Winnie -
This is the code used when kids pee in the swimming pool at Disneyland.
Code Bravo -
This a general security alert code used in airports.
In aviation, this code means that there is a problem with radio communications.
U.S. police use a whole lot of 10s - American police have a number of codes starting with number 10. Examples include 10-35 for a major crime alert, and 10-89 for a bomb threat.