Initialism of special effects.

(historical) 1 November 1945, the planned date for the Allied invasion of Kyushu in southwestern Japan in World War II (cancelled following Japan's unconditional surrender in September 1945).

Synonym of D-Day (“the date of any major event planned for the future”)

(UK) A list of commercial (non-government) sites in United Kingdom territories that are approved to hold confidential information.

(US, military) Any of a series of experimental aircraft and rockets, used to test and evaluate new technologies and aerodynamic concepts.

plural of X-plane

plural of X-ring

plural of X-factor

Abbreviation of King's Cross.

A convention whereby Esperanto’s circumflex accents (ĉ, ĝ, ĥ, ĵ, ŝ, ŭ) are replaced by an x after the non-diacriticked letter (cx, gx, hx, jx, sx, ux), for convenience of typing.