Boyd’s Bible Dictionary:
(bar). A bar of wood or metal for outer, and bolt for inner, doors (1 Kings 4:13; Judg. 3:24).
Concise Bible Dictionary:
These in the East were anciently very rude contrivances. They were made of wood with long wooden bolts into which were driven a few pins which dropped into holes and held the bolt secure. The key, also of wood with corresponding pins, would raise the pins of the bolt, and allow it to be shot back (Judg. 3:23-24; Neh. 3:3-15; Song of Sol. 5:5).
Strong’s Dictionary of Hebrew Words:
Meaning:
from an unused root meaning to fasten on; a veil