Durchbruch
Durchbruch (Ger., breakthrough), a frontal attack intended to split the enemy in two and defeat him. It puts the attacker at risk of being taken in flank, i.e. being flanked, and has thus far only rarely succeeded on a large scale; see also breakthrough battle, breakthrough tank, strategic breakthrough.
The wedge is exceptionally well-suited to bringing about a breakthrough of the enemy front.
Source: Meyers Großes Konversations-Lexikon, 6. Auflage 1905–1909
Durchbruch (Durchbruchsangriff; Ger., breakthrough attack), the continuation of a successful Einbruch (penetration) into the enemy position, with the intention of cutting through the enemy front, enveloping the flanks of the breakthrough point, and rolling up the position.
Source: Kühlwein, Oberstleutnant: Die Gruppe im Gefecht (Berl. 1937)