What is a spacecraft?

NASA uses the term spacecraft to mean devices, either manned or unmanned, which are designed for spaceflight. That is, for flight in the vacuum of space.

NASA literature is replete with phrases like ". . the Pioneer spacecraft returned the first detailed information on the planets Venus, Jupiter and Saturn." And, ". . . Network used for tracking planetary exploration spacecraft such as the Voyagers, Vikings and Mariners

The Wikipedia article linked below does a good job of explaining the meaning of the term spacecraft. A spacecraft is a machine designed by humans to function by human control in space. All manned orbital vehicles are technically spacecraft, as are those remotely controlled from the Earth. Some aircraft have the capability to reach altitudes associated with space, but only for short times and distances. These are not considered true spacecraft.