Padraig Mac Giolla-Domhnaigh

Lamb—This name is the anglicised form of O'Loan in Orghiall, County Louth and Cavan; in Gaelic O'Luain. The Staff of St. Dympna was kept at Tydavnet (Tigh-Damhnat)—House of Damhnat), Co. Monaghan, for many generations in the family of O'Loans who later anglicised the name Lamb.

Alphabetical Index of Anglicised Surnames in Ireland

See also Woulfe’s Irish Names and Surnames
and O'Hart's Irish Pedigrees