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 and Mc together A 2007 book in its tenth edition states that "most library catalogs" sort Mac and Mc names as if spelled M-a-c. Among the guides which generally recommend separating Mac and Mc so that names will be sorted as they are spelled are ISO 999, The Chicago Manual of Style, "Butcher's Copy-editing: The Cambridge Handbook for Editors, Copy-editors and Proofreaders", "The New York Times Manual of Style and Usage", and "The SBL Handbook of Style". Mac and Mc together A convention of sorting names with the Scottish and Irish patronymic prefixes Mac and Mc together persists in library science and archival