Jund has use army
Origin
The term jund derives from Parthian or Iranian word of "Gund" which was later on adopted by Islamic armies after the conquest of Iran. Today, "Gund" still refers to "town, village" as well as gathering (military) in Kurdish which was passed to Arabic with similar meaning of a group of supporters (also could refer to a group in general like in a city) Lisan al-Arab , and appears in the Quran to designate an armed troop. Under the Umayyad Caliphate it came to be applied in a more technical sense to "military settlements and districts in which were quartered Arab soldiers who could be mobilized for seasonal campaigns or for more protracted expeditions" as well as the "corresponding army corps" (Dominique Sourdel). We can observe the same word for a castle (Qalat Al-Gundi or Qalat Al-Jundi) built by Kurdish troops of Saladin in Sinai Peninsula.
Gradually, however, and aside from its technical use for the provinces of Syria (see below), the term acquired a broader meaning of the entire armed forces of a state. Thus one of the caliphal fiscal departments, the diwan al-jund, administered the pay and provisions of the army. In addition, the geographers of the 9th–10th centuries used the term ajnad as an equivalent of amṣar or large towns.