16th cent. Borrowed from Old French bande 'id.,' itself borrowed from Old Occitan banda "regiment." Prior to the modern military sense, banda had been borrowed from Old French bande "group" in the 14th cent. to mean "flock," but was replaced by the later meaning. Borrowed from Gothic *bandwa "sign." A *bandwa referred to the banner or flag carried by a regiment, and was later applied to the regiment itself.
From Proto-Germanic *bandwa- 'id.' Frorm Proto-Indo-European *bhonh2-tu̯éh2- 'id.' From the verb *bhó-n-h2-e- "to summon." From the root *bheh2- "to say" (see hablar).
Gothic bandwo, Old Norse benda "to signal"