A ship is, by definition, a large vessel for navigation purposes. Spaceship is an adaptation from spacecraft to specify that it is 'manned', and spacecraft is a vehicle designed for space. 'Craft' means power, strength, skill or requiring skill, and as well as originating from the items that skilled craftsmen would create, was later used as a nickname for original ships, possibly for a multitude of reasons, such as the skill required to build the vessel, to control it, or the general importance and power of using it for trade between communities.