mortise lock BrE
dead bolt AmE

At night we have a dead bolt on the door.

At the back door, I tried the dead bolt again.

Nobody had a key to the dead bolt, not even her mother.

I pushed the dead bolt back and opened the door.

I needed to put a dead bolt on the inside of the door; that would be even better.

He heard a key hit the dead bolt on the other side of the front door.

He paused only long enough to close the door and turn the dead bolts.

He locked the front door, but did not turn the dead bolt.

She locked her front door and turned the dead bolt.

Tonight he would have to do without the dead bolt.