Code Oscar: On a ship, a code oscar means someone has gone overboard. If the ship has to maneuver erratically to handle the situation, it must also send out blasts on the signal so that other ships nearby are aware of the fact that it is about to change its course. It should be noted that ships don’t have an internationally standardized set of PA signals and they can differ from place to place, but this is a fairly commonly used one.
Code delta: can mean that there is a biological hazard - though who knows what that might be on a passenger ship.
Code Alpha: often means “medical emergency”.
Code Adam: was invented by Walmart but it is now an internationally recognized alert. It means “missing child”. The code was first coined in 1994 in memory of Adam Walsh, a six-year old, who went missing in a Sears department store in Florida in 1981. Adam was later found murdered. The person making the announcement will state “we have a code Adam,” followed by a description of the missing child. As soon as the alert is heard, security staff will begin to monitor the doors and other exits. If the child is not found within 10 minutes, the police are alerted and a store search begins. Also, if the child is found in the first 10 minutes in the company of an unknown adult, the police must be called and the person detained if it is safe to do so.
Secret Codes You Aren’t Meant To Know