bulkhead

Meanings

1. A vertical partition dividing the hull into separate compartments; often made watertight to prevent excessive flooding if the ship's hull is breached.
2. A similar partition in an aircraft or spacecraft, or some rail vehicles.
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. A cellar hatchway.

Etymology

From Old Norse bálkr (“partition”) + head, anglicised as bulk + head.