lock out

Meanings

1. To inadvertently prevent (a person, particularly oneself) from entering a place, by leaving it locked.
2. To prevent from accessing a data structure.
3. (industrial) 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)
4. (colloquial, sometimes humorous) To be unable to concentrate.

1. Misspelling of lockout.