(astronomy) A hypothetical planet in the Solar system, beyond the currently known outermost planet. (The term was applied to Eris for a short while, when Pluto was still considered the ninth planet.)

present participle of X-ray

simple past tense and past participle of X-ray

A SAMPA-inspired transcription of the International Phonetic Alphabet (IPA) into ASCII.

plural of X-chromosome

tic-tac-toe / (idiomatic, sports) The fundamental elements of a play. / (idiomatic, management) The basic delineation of roles in a project.

(algebraic geometry) The direction aligned with the x-axis of a coordinate system.

(idiomatic) An unknown or hard-to-define influence; a factor with unknown or unforeseeable consequences. / (idiomatic) A special talent, ability or quality or its indefinable cause.

plural of x-factor

plural of X factor