Bulkhead

noun

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.
3. Mechanically, 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.