1.verbTo keep safe; to defend; to guard; to prevent harm coming to.
"Condoms are designed to protect against sexually-transmitted diseases."
2.verb(travel) To book a passenger on a later flight if there is a chance they will not be able to board their earlier reserved flight.
3.adjectiveDefended
4.adjective(of a variable, method, etc.) Having the protected access modifier, indicating that a program element is accessible to subclasses but not to the program in general.