In Gallo-Roman religion, Ambisagrus was a Gaulish god worshipped at Aquileia in Cisalpine Gaul, where he was identified with Jupiter Optimus Maximus.
The name may be composed of the Proto-Celtic prefix *ambi- ('around') and root *sagro-.
John T. Koch has suggested that this Jovian epithet may originally have applied to Taranis, with allusion to the tendency of thunder near an observer to seem all-surrounding.
References
Ambisagrus Wikipedia(Text) CC BY-SA