My great grand-father's birth certificate has an additional name in brackets after our family name.
For example: First Middle Family (Davies)
He was born 1883 in Llanelly, Breconshire and wondered what the significance of the inclusion of the Davies name could mean. Is it common for this to be on birth certificates of the time? It doesn't match the mother's maiden name of Jones, although there had been the family suggestion he was actually adopted into the family. Maybe a pure coincidence, but the 1881/1891 welsh census has a Davies family as neighbours.