bolt

At last however about two in the morning, I suddenly heard the gentle sound of a bolt being pushed back and the creaking of a key.

Then from the pocket of his overcoat he drew a bulky object, and he busied himself in some task which ended with a loud, sharp click, as if a spring or bolt had fallen into its place.

There is no bolt-hole for you in this country.

One struck, and two, and we had almost for the second time given it up in despair when in an instant we both sat bolt upright in our chairs with all our weary senses keenly on the alert once more.