(chiefly US) An extraterrestrial being; a visitor from outer space.

plural of illegal alien

A small religious house dependent on a large monastery in some other country.

plural of alien priory

plural of alien abduction

plural of casual alien

(botany) A plant that appears with no apparent human assistance but does not develop a sustained population.

(fandom slang) April 26, as a "fan holiday" celebrating the science-fiction horror franchise "Aliens". The date 4/26 is in reference to fictional planet LV-426 where the Xenomorph was first unveiled.

Any nucleic acid composed of bases other than adenine, guanine, thymine, uracil and cytosine and/or sugars other than ribose and deoxyribose, that could form the basis of extraterrestrial carbon-based life.

plural of alien nucleic acid