uchronian adjective2 •Pertaining to uchronia ("an idealized or fictional conception of a particular period of time, especially in the past").For a long time to come, at least, it is too dangerous an experiment to base on hope. Again they may say that it never could succeed unless in a uchronian Utopia 'above these ruinable skies'. — 1945 •Pertaining to uchronia (meaning alternate history) formsmore uchronian · most uchronian