Beings or life forms that come from outside Earth, such as aliens from other planets or galaxies.
From Latin 'extra' meaning 'outside' plus 'terrestris' meaning 'of the earth.' The term was constructed in English during the space age (mid-20th century) as science fiction and astronomy developed, combining classical roots to describe something that had never been formally named before.
Scientists actually debate whether extraterrestrials exist so much that they created the 'Drake Equation' in 1961 to calculate how many intelligent alien civilizations might be out there—and the numbers suggest we probably aren't alone, which makes this word describe something we might legitimately discover someday.
Complete word intelligence in one call. Free tier — 50 lookups/day.