EtymologyMacGuinness is a variant of McGuinness, itself an Anglicized form of the Irish patronymic Mag Aonghuis, meaning “son of Aonghus”. The name thus traces back to a personal name of great antiquity in Irish mythology and history. The underlying Gaelic name Aonghus (anglicized as Angus) is believed to derive from Old Irish Óengus, composed of óen “one” and guss “force, strength”, giving the meaning “one strength”.Mythological and Historical SignificanceAonghus (also known as Mac Óg or “young son”) is a prominent figure in Irish mythology, one of the Tuatha Dé Danann. He was the god of love and youth, the son of the Dagda and Boann. The name was also borne by an 8th-century Pictish king, several Irish kings, and a few saints, including a 9th-century bishop of Tallaght. The later Patronymic surname thus connects bearers to this rich mythological and historical ancestry.Distribution and VariantsThe surname MacGuinness and its many variants—such as Guinness, MacGinnis, McGinnis, and McGuinness itself—reflect the anglicization and regional variation of the original Gaelic original Mag Aonghuis. In Scotland, related forms include MacAonghais (Scottish Gaelic), Angus, Innes, MacAngus, MacInnes, and McInnes.According to Forebears, the surname MacGuinness itself is found in small numbers today, primarily in Ireland and the United Kingdom.Key FactsMeaning: Son of Aonghus (“one strength”)Origin: IrishType: Patronymic surnameRegions: Ireland, United Kingdom, also found in diaspora (USA, Canada, Australia)