Probable actual name of the god the Romans called Gaulish Mercury. The name survives in inscriptions found in Avenches, Switzerland, and is implicit in the Roman town name Lug[u]dunum, the basis of the modern Lyon, Laon, Leiden, Loudon, Liegnitz, Léon, Dinlleu, and Luguvalium, antecedent of Carlisle. He would also be the Gaulish counterpart of Irish Lug Lámfhota and the Welsh Lleu Llaw Gyffes. Another possible name for Mercury is Erriapus.
See E. van Tassel Graves, ‘Lugus, The Commercial Traveller’, Ogam, 17 (1965), 165–71;A. Zooa, ‘The God Lugus in Spain’, Bulletin of the Board of Celtic Studies, 29 (1980–2), 201–29.