n. a non-keyed deadbolt, with a one piece escutcheon/faceplate, typically mounted flush to door surfaces

A door bolt that is flush with the face or edge of the door. For use on a dummy door.

A bolt that is mortised into the edge of a door that will lock either or both the top and bottom of the door. Usually used on a pair of doors so that one door will remain closed or inactive, allowing the other door to lock into it.

The locking devise mortised into an astragal which secures the astragaled door of a pair of doors in a closed position. The flush bolt engages in the sill and the header to hold the door in the closed position.