bottom bolt

noun

1. a bolt at the bottom of a door or the like, sliding into a socket in the floor or sill and equipped with a device for keeping it raised when the door is not fastened.

Example Sentences

Then I silently shot the bottom bolt and noisily drew back the top one.

From Project Gutenberg

It is not true that the bottom bolt was never used to secure the door; it was bolted that night.

From Project Gutenberg