What does bulkhead mean?
A bulkhead is an upright partition that divides the interior of a ship, aircraft, or other vehicle into separate compartments. Its best-known role is nautical: watertight bulkheads segment a ship's hull so that if one compartment floods, the others remain dry, greatly improving the vessel's chances of staying afloat after hull damage. The term extends naturally to aircraft fuselages and vehicles, where bulkheads add structural strength and separate functional zones, and in construction it can describe retaining walls or partitions holding back earth or water. The word dates to fifteenth-century maritime usage, combining 'bulk' (the ship's cargo hold, from Old Norse) with 'head'. Because of its prominence in disaster narratives and engineering discussions, 'bulkhead' is a precise, widely understood term for anyone describing how large vessels and craft are internally structured and protected against catastrophic failure.
nounA partition wall or dividing structure, typically in a ship or aircraft, that separates compartments and can help contain flooding, fire, or pressure; more broadly, any similar dividing barrier in a building, vehicle, or container.
- An upright partition dividing a ship into compartments, especially one designed to be watertight so flooding does not spread.
- A similar dividing wall or panel in an aircraft, spacecraft, road vehicle, or railway car, often providing structural rigidity.
- A retaining wall or chamber built at the edge of water or earth, such as one holding back soil or forming part of a dock or cellar entrance.
"The crew sealed the watertight bulkhead to keep the flooding confined to the engine room."
"The submarine's designers added extra bulkheads so that damage to one compartment would not sink the vessel."
"He stowed his bag behind the rear bulkhead before climbing into the cockpit."
Regular plural formation; used when referring to multiple compartments' partitions or several vessels' structures.
"The ferry was retrofitted with additional bulkheads to meet modern safety standards."
The word 'bulkhead' literally means the 'head of the cargo hold' — the partition that keeps a ship's bulk (cargo) from shifting, and it's the reason Titanic-style ships could theoretically survive being holed.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bulkhead
The word 'bulkhead' arose in late Middle English, first attested in maritime contexts in the fifteenth century. It combines 'bulk', meaning the cargo hold of a ship (from Old Norse 'bulki'), with 'head', here meaning a partition or end structure. Originally it denoted partitions protecting the cargo hold, and the meaning broadened over time to any compartment-dividing wall aboard ships and later in aircraft and vehicles. The element 'bulk' also yields 'bulky', making these true relatives rather than unrelated coincidences.
How bulkhead is actually used
'Bulkhead' is a technical term most common in maritime, aviation, and engineering contexts, but it is well understood in general English thanks to its frequent appearance in accounts of shipwrecks and disasters. It carries no emotional connotation and is neutral in register. In everyday speech it is occasionally used loosely for any sturdy internal partition.
Easily confused with bulkhead
A bulwark is a defensive rampart or protective barrier (or a figurative safeguard), whereas a bulkhead is an internal dividing partition within a ship, aircraft, vehicle, or structure.
Bulk refers to mass, volume, or size, while a bulkhead is the physical partition whose name derives partly from that word.