bulkhead

Short definition from Wiktionary

Noun

1. 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. 2
   A similar partition in an aircraft or spacecraft.
3. 3
   A partition or panel through which connectors pass, or a connector designed to pass through a partition.
4. 4
   A pressure-resistant sealed barrier to any fluid in a large structure.
5. 5
   A retaining wall along a waterfront.
6. 6
   A cellar hatchway.