From a Norman baronial surname, from a place in France, Old French del aunaie "from the alder grove". In Ireland an anglicization of Irish Ó Dubhshláine "descendant of Black (dubh) + Challenge (slán)".
- 1945 Tennessee Williams, The Glass Menagerie, Scene V:
- TOM. James D. O'Connor. The D. is for Delaney.
- AMANDA. Irish on both sides! Gracious! And doesn't drink?