The name Fennelly in Ireland is derived from the native Gaelic O'Fionnghalaigh Sept that is taken from Gaelic words that translate as 'fair valour'. Descendants bearing this name can still be mostly found in the ancestral homeland Counties of Kilkenny, Tipperary and Offaly.

Origen: Normando. The name Fennelly is part of the ancient legacy of the Anglo-Saxon tribes of Britain. It is a product of when the family lived near a place where vennel grew. Vennel was an herb used for cooking. Other sources list the name as a local name derived from the term at the vennel. First found in Norfolk where they were seated from very ancient times, some say well before the Norman Conquest and the arrival of Duke William at Hastings in 1066 A.D.

Variantes: Fennelly, Fennell, Vennell, Venall, Fenel y otros.