GUARD

Guard is a term used to describe a person, device, or action that protects from harm or danger or that watches over something. As a verb, to guard means to watch over, protect, or secure against loss, damage, or intrusion. The word is widely used in security, safety, sports, and computing.

In people, a guard is someone assigned to protect people or property, including security guards, bodyguards, museum guards, and railway guards who oversee safety and operations on trains. In team sports, guard denotes a playing position, notably the point guard and shooting guard in basketball, and the guard positions on the offensive line in American football.

In equipment and infrastructure, guards serve as protective devices: guard rails on roads or platforms, machine guards that prevent contact with moving parts, and protective wear such as mouthguards and face guards.

In computing and logic, a guard is a conditional check used to control flow. Guard clauses return early if a condition is not met, and languages such as Haskell use guards to select between alternatives.

Related uses include guarding against risks in everyday life, such as guarding valuables or guarding a route to prevent unauthorized access. The term also appears in medicine, where protective guards may be used to shield patients or equipment, and in manufacturing, where machine guards help reduce the risk of injury. Overall, guard denotes both a person who protects and the means of protection across various contexts.