Other forms: bulkheads
A bulkhead is a wall dividing a ship into watertight sections. Watertight bulkheads, the forward bulkhead, a bulkhead door.
The point is that a hole in one compartment floods only that compartment, which is what keeps a damaged ship afloat. The Titanic's bulkheads did not reach high enough, so water spilled over the tops from one compartment to the next. Aircraft have them too, and a bulkhead seat is the one with a wall in front and no seat to recline into you.
1nounbulkheadA wall dividing a ship into watertight sections.
“The crew shut the doors in the bulkheads to stop the water flooding the whole ship.”
bulkhead is a dividing wall.
The word joins Old Norse balkr, a partition, to head. Balk and baulk come from the same partition, meaning a ridge or barrier.
Old Norse
bálkr — partition
English, today
bulkhead
From Old Norse bálkr (“partition”) + head, anglicised as bulk + head.
Etymology from Wiktionary, CC BY-SA