Definition of "beag"

It was a mark of nobility among the German races — by some considered the origin of our coronets — and had even about it a quasi-religious character in memory of the "holy beag" (holy ring), the oath upon which was tantamount to the oath upon Thorr's hammer.

1878, The Numismatic chronicle and journal of the Numismatic Society, Great Britain: Royal Numismatic Society

[...] and the description of that monarch in his anonymous Vita as coronatus lauro probably indicates a beag which was lighter than the formal diadema.

1970, William A. Chaney, The cult of kingship in Anglo-Saxon England