What is the meaning of Lock_out?

To inadvertently prevent (a person, particularly oneself) from entering a place, by leaving it locked.

To prevent from accessing a data structure.

To prevent (a person, including oneself) from powering up or turning on a machine when doing so would be dangerous (accomplished with objects such as padlocks or zip ties placed through the switch handle, for example)

to be nothing for Halloween.

Misspelling of lockout.

Source: wiktionary.org