This glossary defines the various types of ships and accessory watercraft that have been used in service of the United States. Such service is mainly defined as military vessels used in the United States Navy and United States Coast Guard, as well as the defunct, incorporated, or renamed institutions such as the United States Revenue Cutter Service. Service of the United States can also be defined in this context as special government missions in the form of expeditions, such as the Wilkes Expedition or the North Pacific Exploring and Surveying Expedition. The scope of the glossary encompasses both the "Old Navy" of the United States (sail or later steam vessels, with ship type named for the rigging or propulsion method [ex. steamer, cutter, schooner]), from its beginnings as the "Continen