Definition: The term "lock out" is primarily used as a verb, meaning to prevent employees from entering their workplace, usually during a labor dispute or strike. This is done by the employer to pressure workers into accepting certain conditions or to prevent them from working when they are on strike.
In more complex discussions, "lock out" can also refer to security measures taken to prevent unauthorized access to a system or facility, but this is less common. For example, in the context of technology, it might refer to being denied access to a computer system due to incorrect passwords.
"Shut out": This can be used similarly to "lock out" but is more general and can refer to being excluded from any situation, not just employment.
In summary, "lock out" is a term used in labor disputes to describe a situation where employers prevent employees from working, particularly during strikes.