Definition of "bulkhead"

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

(aerospace) A similar partition in an aircraft or spacecraft.  examples

(mechanics) A partition or panel through which connectors pass, or a connector designed to pass through a partition.  examples

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

A retaining wall along a waterfront.  examples