The spelling of Oxborough is, if I’m being honest, a bloody nuisance as it differs from Oxburgh Hall which uses an old spelling of the village. So, that gives lots of room for error in writing about the National Trust property. Anyway, The Concise Oxford Dictionary Of English Placenames says:
Oxborough, Norfolk. Oxenburch in Domesday Book, Oxeburg in 1194. Where oxen were kept.
A burgh, or borough, in this context means a settlement, so a settlement which had oxen. The spelling has varied over the centuries, including Oxburgh, Oxborough, Oxborrow and many others.