What is the meaning of Bulkhead?

A vertical partition dividing the hull into separate compartments; often made watertight to prevent excessive flooding if the ship's hull is breached.

A similar partition in an aircraft or spacecraft.

A partition or panel through which connectors pass, or a connector designed to pass through a partition.

A pressure-resistant sealed barrier to any fluid in a large structure.

A retaining wall along a waterfront.

A cellar hatchway.

Source: wiktionary.org