Costello (surname) to a Gaelic translation of Jocelyn, Jocelyn d'Angulo's given name. In fact, MacOisdealbhaigh is the Gaelic translation of his brother Hostilo (or Hostilio) d'Angulo's first name. Oisdealbh is a much more obvious translation of Hostilo. It is Hostilo's descendants who would bear the surname Mac Oisdealbhaigh (son of Oisdealbh or Hostilo). The surname would later be anglicized to Costello, Costelloe, and Costellow. Gilbert d'Angulo is also sometimes listed as the son of Jocelyn d'Angulo in error. Gilbert d'Angulo is the father of both Jocelyn and Hostilo. It occasionally has been adopted as a pseudonym or stage name by famous people
Mac Amhalghaidh "Nic Amhalghaidh". This feminine surname is actually a contracted form of "iníon Mhic Amhalghaidh", which translates into English as "daughter of "Mac Amhalghaidh"". The form of the surname for married females is "Bean Mhic Amhalghaidh", which translates into English as "wife of "Mac Amhalghaidh""; this feminine surname can also be represented in the contracted form "Mhic Amhalghaidh". A cognate of the Irish "Mac Amhalghaidh" is the Scottish Gaelic "MacAmhalghaidh". The feminine form of this Scottish Gaelic surname is "NicAmhalghaidh". This feminine name is composed of the prefix "Nic-", which is an abbreviated form of the Scottish Gaelic "nighean mhic" or