(an arbitrary designation for) an unknown or hypothetical alien planet
In early use, in Astronomy: a hypothetical undiscovered planet in the solar system, whose supposed orbit lies beyond that of the outermost planet known; (originally) that identified as the ninth planet and named Pluto; (later) a hypothetical planet or planets beyond Pluto
The distance of ‘planet X’ from the sun has been estimated at Flagstaff as 45 times the distance of the earth from the sun.]
We can only speculate about knowledge on Planet X if we speculate on the general way its inhabitants live and relate.
The scrambler denatured her voice, made her sound like a creepoid from Planet X.
[H]earing a bush speak...could happen easily in a fairy tale, however, or a ‘fable’ like Alice in Wonderland, or in a Greek myth at the point at which some hapless maiden is being transformed into a sapling or other item of vegetation by a god. And it could happen effortlessly on Planet X.
Last modified 2021-02-06 21:13:56
In the compilation of some entries, HDSF has drawn extensively on corresponding entries in OED.