D

deadbolt
A lock bolt, usually rectangular, that has no spring action, and that becomes locked against end pressure when fully projected.

deadlatch
A lock with a beveled latch bolt that can be automatically or manually locked against end pressure when projected.

deadlock
A lock that projects a deadbolt.

depth
The depth of a cut is measured from the bottom of the blade up to the bottom of a cut. Depths are numbered starting with #0 (or sometimes #1) as the highest depth.

depth key
A special key that enables a locksmith to cut blanks made from a particular lock according to a key code.

display key
n. a special change key in a hotel master key system which will allow access to one designated guest room, even if the lock is in the shut out mode. It may also act as a shut out key for that room.

drivers
The pins in a lock that sit on top of the lower pins.