LUGDUNUM (anc. geog.), the capital of the Seugiani in Gallia Celtica, situated at the conflux of the Arar and Rhodanus, on an eminence, as the Celtic term dune signifies; built by Manutius Plancus under Augustus, while commanding in that part of Gaul; and whither he led a colony. Now Lyon, capital of the Lyonois.