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I / I-Branch: Intelligence branch.
Iddy-umpty: slang for a signaller.
Ideflieg : Inspekteur der Flieger, German Inspector General of Aviation.
Identification disc: Tags bearing a soldiers name, number and unit.
IG: Inspector General.
Igaree: Australian term for ‘hurry up’.
Ikhtiat: Turkish regular reserves.
Ilaweh: Turkish second reserves.
Iluft : Inspektion der Luftschiffertruppen, German inspectorate of balloon units.
Imshi: Arabic for ‘go away’, used by UK and ANZAC troops; also used as a battle cry at Gallipoli.
Independent Air Force: The arm of the RAF devoted to strategic bombing; ‘independent’ because it operated independently of ground commanders and their front line needs.
Indicator Nets: Nets hung down into a waterway at various depths to ‘catch’ submarines; marker buoys were attached to the nets, giving a clear indication of both a sub’s presence and location.
Infanterie-Ersatz-Truppe: German infantry training centre.
Infanterie-Geschütz: Russian 7.62mm field gun having been captured and issued to German forces.
Interrupter Gear: A modified applied to an aircraft which enabled machine guns to fire through a plane’s propeller without causing damage, as a connection between the propeller and gun caused the latter to stop whenever they were aligned. Enabled more accurate firing.
Intervalle: French for a trench bay.
Iron Ration: The emergency rations carried by soldiers for when normal food could not be supplied. The British iron ration was corned beef, biscuit, tea and sugar.
Irredentism: An Italian movement wishing to unite national groups within one nation/claiming territory on the grounds of language and race; similar movements started in other nations.
IS: ‘Imperial Service’, Indian state troops loaned to the national government.
Isolationism: Staying totally out of world affairs, most famously practiced by the United States in the early part of the twentieth century.
Italienisches MG : Austrian term for captured machine guns which were reissued to planes.
ITD: Infaterie-Truppen-Divisionen, Austro-Hungarian infantry divisions.
IWT: Inland Water Transport, the British unit responsible for canals on the Western Front.