Armeegruppe was a historical type of major formation of German military history, in use in the Imperial German Army during World War I and the Wehrmacht during World War II.
While the term literally translates as army group, the German-language equivalent of an English-language army group is Heeresgruppe. Whereas a Heeresgruppe-type army group was designed to be permanent, an Armeegruppe-type army group was usually an ad hoc formation for a specific military task. Typically, Armeegruppe-type formations were short-lived.
Whereas Heeresgruppe-type formations were typically named after a geographic region (such as Heeresgruppe Courland), geographic direction (such as Heeresgruppe North) or even named by simple letters (such as Army Group A), Armeegruppe-type army groups were typically named after their commanding general, e.g. Army Group Steiner was named after Felix Steiner.
The Wehrmacht of World War II was peculiar compared to the German army of World War I due to its much stronger inclusion of allied armed forces (such as the Royal Italian Army or Royal Hungarian Army), and Armeegruppe-type army groups were once again revived to serve as ad hoc combinations of an army-level command, typically German, which would take the lead, and a second army-level command, typically of another Axis country, which would be subordinate. Exceptions from this rule were Army Group Dumitrescu, when a non-German army (in this case 3rd Romanian Army) was superior to a German army (in this case 6th Army) and Army Group Felber, which was only of corps-strength and would typically have been referred to as a 'Gruppe' rather than 'Armeegruppe' if Wehrmacht precedent had been followed more closely. Additionally, Army Group G and Army Group Liguria were not named after commanders but instead after a letter or a region, respectively; Army Group G was later upgraded to Heeresgruppe-level.