blkd.

Noun

bulkhead (plural bulkheads)

1. A vertical partition dividing the hull into separate compartments; often made watertight to prevent excessive flooding if the ship's hull is breached.
   • Lastly, Lundberg went belowdecks to inspect the boat's bulkheads and hull—for what, it was not clear, since he had absolutely no knowledge of steamboat design.2003, Edward T. O'Donnell, Ship Ablaze: The Tragedy of the Steamboat General Slocum, page 54
2. A similar partition in an aircraft or spacecraft, or some rail vehicles.
   • For rigidity, two bulkheads are provided which are welded to the sides and underframe and which separate the cabs from the engine room.1958 September, “Swindon's First Main-Line Diesel Locomotive”, in Railway Magazine, page 601
3. A partition or panel through which connectors pass, or a connector designed to pass through a partition.
4. A pressure-resistant sealed barrier to any fluid in a large structure.
5. A retaining wall along a waterfront.
6. (Maine, Rhode Island, Massachusetts) A cellar hatchway.
   • She bumped her noggin on the bulkhead above the doorway, smiled in apology for her presumed clumsiness.2003, John Farris, The Fury and the Power