Battles & Operations: translations German-English

Unternehmen: can be translated as 'enterprise', used by the Germans in WWII when they wanted to keep planned operations such as 'Unternehmen Barbarossa' or 'Unternehmen Zitadelle' a secret to the enemy.

Another example is Unternehmen 'Wacht am Rhein' better known as the "Von Rundstedt offensive" or "Ardennen offensive" translated as Operation The Guard on the Rhine or Operation "Watch on the Rhine" and known on Allied side as 'Battle of the Bulge'.
The choice of words was carefully choosen so when the name was discovered the Allied would have thought that it was a defensive operation to protect the Rhine.

Operation: the word 'Operation' is both used in English and German.

Schlacht: in English "Battle"

Gefecht: in English "Fight", multiple "gefechten" become a "slacht".

Scharmützel (Treffen): unplanned fights, fights that don't belong to a planned battle or operation.

Feuergefecht: a "gefecht" between 2 opposite forces using fire-arms.

Belagerung: Siege, encirclement of forces within a 'stronghold' (encirclement of Best Litvosk)

Kesselschlacht / Umfassungsschlacht: encirclement: a "belagerung" but without the presence of a 'stronghold' (Battle of Dunkirk)