Costello Family History
Costello Name Meaning
Irish: shortened Anglicized form of Gaelic Mac Oisdealbhaigh ‘son of Oisdealbhach’ a personal name composed of the elements os ‘deer fawn’ + dealbhach ‘in the form of resembling’. Americanized form of Italian Castello and also of some other surnames beginning with Cast- for example Castelluccio . Americanized form of Croatian Kostelac and Slovenian or Croatian Kostelec or Kostevc.
Source: Dictionary of American Family Names 2nd edition, 2022