A lazarette (also spelled lazaret) is a special area on a boat. It is often an area near or aft of the cockpit. The word is similar to and probably derived from Lazaretto.
A lazarette is usually a storage locker used for gear or equipment a sailor or boatswain would use around the decks on a sailing vessel. It is typically found below the weather deck in the stern of the vessel and is accessed through a hatch if accessed from the main deck or a doorway if accessed from below decks. The equipment usually stored in a lazarette would be spare lines, sails, sail repair, line and cable splicing repair equipment, fenders, bosun chair, spare blocks, tools etc.
In modern shipbuilding and for powerboats of most sizes, the lazarette is the location of the steering gear equipment for the vessel. This area is particularly sensitive to flooding and damage, as the ability to steer during heavy weather is of the utmost importance to vessel safety. The lazarette also represents a vulnerability in that the large hull penetrations required for rudders and shafts for propulsion through the vessel's hull generally reside there.