from The Century Dictionary and Cyclopedia
- n. The middle transverse rail of a door, at about the level of the hand, on or in which the lock is generally set.
- n. In some door-frames, a crosspiece dividing the doorway from an open space above it in which a glazed sash is usually placed; a transom.
Sorry, no etymologies found.
"lock-rail" (where the door-knob and lock are inserted), and sometimes the "frieze-rail" between the lock rail and the top rail.