An Etymological Dictionary of the German Language/Burg
Burg, f., ‘stronghold, citadel, castle, fortified town,’ from MidHG. burc(g), OHG. burg, burug, f., ‘enclosed, fortified place, stronghold, castle, town.’ Comp. OSax. burg, Du. burg, AS. burh (plur. byrg), E. borough, bury, burrow (especially in compounds), Goth. baúrgs. In the OTeut. dialects Burg corresponded to the modern town. Ulfilas translated πόλις by baurgs. According to the Germania of Tacitus, the Teutons had no urbes, but their oppida were mentioned as early as Cæsar (De Bell. Gall.). With Gr. πύργος, ‘tower,’ the OTeut. Burg accords neither in form nor meaning. The OTeut. word appears strangely enough in Armen. as burgu, and in Arab. as burǵ, which probably owed their immediate origin to late Lat. burgus (whence the Rom. words Ital. borgo, Fr. bourg, ‘market town’; so too OIr. borg, ‘town’). In this sense the word is solely Teut., and belongs with Berg to an Aryan bhṛgh-, which also appears in OIr. bri (gen. brig), ‘mountain, hill,’ but scarcely to the verbal stem of bergen. The words for ‘town’ were not formed until the separate Aryan tribes ceased their wanderings and became permanent settlers; comp. also Garten.