A holster is a specially designed holder, usually made of leather or sturdy fabric, that keeps a handgun secure and accessible on someone's body. Police officers wear holsters on their belts so their weapons stay in place while they walk, run, or drive, but can be drawn quickly if needed. Cowboys in the Old West wore holsters on their hips, and you've probably seen them in Western movies.

A holster serves two important functions: it protects the trigger from being accidentally pressed and helps keep the weapon pointing in a safe direction. A good holster holds the gun firmly enough that it won't fall out during normal movement, but allows the user to pull it free smoothly when necessary.

You might hear someone say they holstered their weapon, meaning they put it back into the holster. The word can occasionally be used for other items too: a construction worker might holster their hammer in a tool belt loop, borrowing the term from its original use.