In Gallo-Roman religion, Ambisagrus was a Gaulish god worshipped at Aquileia in Cisalpine Gaul, where he was identified with Jupiter Optimus Maximus.L'Arbre Celtique entry for Ambisagrus.
The name may be composed of the Proto-Celtic prefix *ambi- ('around') and root *sagro-.Proto-Celtic—English lexicon. University of Wales Centre for Advanced Welsh and Celtic Studies. (See also this page for background and disclaimers.)
Notes
References Peter Berresford Ellis, Dictionary of Celtic Mythology(Oxford Paperback Reference), Oxford University Press, (1994): Juliette Wood, The Celts: Life, Myth, and Art, Thorsons Publishers (2002):