Astronaut, which is derived from words meaning "star sailor," can be used to describe anyone who travels beyond the atmosphere of a planet, but it is usually attached to individuals (or those in small groups) who travel into a local orbit around their homeworld or beyond.

The word astronaut is derived from the Greek words "astron" (άστρον) for "star" and "nautes" (ναύτης) for "sailor." According to Wikipedia the word originated in English as a term for individuals travelling in space in 1930, though it has antecedents dating back half a century earlier.

The first known use of the term "astronaut" in the modern sense was by Neil R. Jones in his 1930 short story "The Death's Head Meteor". The word itself had been known earlier; for example, in Percy Greg's 1880 book Across the Zodiac, "astronaut" referred to a spacecraft. In Les Navigateurs de l'Infini (1925) by J.-H. Rosny aîné, the word astronautique (astronautic) was used. The word may have been inspired by "aeronaut", an older term for an air traveler first applied in 1784 to balloonists. An early use of "astronaut" in a non-fiction publication is Eric Frank Russell's poem "The Astronaut", appearing in the November 1934 Bulletin of the British Interplanetary Society.