K. u. k. Armee

The Common Army (German: Gemeinsame Armee), as it was officially designated by the Imperial and Royal Military Administration, was the largest part of the Austro-Hungarian land forces from 1867 to 1914, the other two elements being the Imperial-Royal Landwehr (of Austria) and the Royal Hungarian Landwehr (or Magyar Királyi Honvédség, colloquially the Honved). However, it was simply known as the Army (Heer) by the Emperor and in peacetime laws, and, after 1918, colloquially called the k.u.k. Armee (short for Imperial and Royal Army).

Established on 15 March 1867 and effectively disbanded on 31 October 1918 when its Hungarian troops left, the Common Army formed the main element of the "armed power" (Bewaffneten Macht or Wehrmacht) of the new double monarchy, to which the Imperial and Royal Navy (k.u.k. Kriegsmarine) also belonged. In the First World War all land and sea forces of the monarchy were subordinated to the Armeeoberkommando set up in 1914.

Until 1889 the armed forces bore the title "k.k." (kaiserlich-königlich i.e. "Imperial-Royal", which was technically incorrect after 1867 for a common institution of both Austrian and Hungarian halves of the Empire), as they had done before 1867. Only on the express wish of the Kingdom of Hungary was the designation "k.u.k." (kaiserlich und königlich i.e. "Imperial and Royal") introduced in order to make the distinction clearer between the new Austrian army, the k.k. Landwehr, and the new Hungarian force, the k.u. Honved. The navy did not use "k.u.k." as often, because there were few other naval forces apart from the main navy.

After the Austro-Hungarian Compromise of 15 March 1867 the army and navy were no longer institutions of a single state, but of the new double monarchy, which was composed of two countries on an equal footing: the Empire of Austria (Cisleithania) and the no longer subordinate Kingdom of Hungary (Transleithania); the two being joined together in a real union.

...
Wikipedia