Order by: alphabetical | chronological
| Word | Definition |
|---|---|
| world-building n. (1920) | the creation of fictional realms and their geology, geography, biology, etc., often including the history and culture of their inhabitants |
| worldcon n. (1952) | the annual world science fiction convention |
| worldlet n. (1841) | a small celestial object; a planetoid |
| worm n. (1975) | a program designed to sabotage a computer or computer network; spec. a self-duplicating program which can operate without becoming incorporated into another program |
| wormhole n. (1957) | an interconnection between widely separated regions of space-time, allowing faster-than-light travel between them |
| xeno- prefix (1962) | (used to form words indicating that the base element is or relates to an alien) |
| xenoanthropology n. (1966) | the study of alien cultures |
| xenobiological adj. (1958) | of or relating to xenobiology n. |
| xenobiologist n. (1954) | one who studies xenobiology |
| xenobiology n. (1954) | the study of the biology of extraterrestrial life forms |
| xenocidal adj. (1979) | of, pertaining to, or involving xenocide n. |
| xenocide n. (1973) | the killing or attempted killing of an entire alien species; the killing of an individual alien; (also) a person who commits this act |
| xenolinguist n. (1955) | one who studies alien languages |
| xenolinguistics n. (1955) | the study of alien languages |
| xenological adj. (1950) | of, or relating to, xenology |
| xenologist n. (1949) | one who studies xenology n. |
| xenology n. (1949) | the scientific study of aliens, esp. xenobiology n. |
| xenopsychologist n. (1980) | an expert in xenopsychology n. |
| xenopsychology n. (1972) | the psychology of alien races |
| X-Phile n. (1994) | a fan of the TV show The X-Files |
| zap gun n. (1934) | = ray gun n. |
| zero-g n. (1940) | = zero-gravity n. |
| zero-gravity n. (1938) | the state or condition in which there is no apparent force of gravity acting on a body, either because the force is locally weak, or because both the body and its surroundings are freely and equally accelerating under the force |
| zine n. (1941) | = fanzine n. |