An abbreviation for Irgun Zvai Leumi (National Military Organization). Established in 1937 as an underground Jewish extremist organization, also known as Etzel, derived from the pronounced initials of its Hebrew name. A more extreme group, known as the Stern Gang (q.v.), broke away from it in 1939. Both groups were especially active during and after World War II against the British authorities in Palestine. Both maintained several thousand armed men until all Israeli forces were integrated in June 1948.

See Etzel.

Irgun (ארגון), shorthand for Irgun Tsvai Leumi (ארגון צבאי לאומי, also spelled Irgun Zvai Leumi), Hebrew for "National Military Organization", was a clandestine militant Zionist group that operated in Palestine from 1931 to 1948. In Israel, this group is commonly referred to as Etzel (אצ"ל), an acronym of the Hebrew initials. In the time in which the Irgun operated, often people referred to the Irgun as 'הגנה ב or ההגנה הלאומית.

A region; roughly equivalent to an SCA Principality