Belisama

Belisama (Gaulish "Belesama"; epigraphically ) is a Gallo-Roman goddess. She was identified by Roman commentators with Minerva by "interpretatio romana". The name also appears in various river names of Gauls and Britain, including "Belisama" (River Ribble) and "Le Blima" (Tarn). 
Name.
The Gaulish theonym "Belesama" has been traditionally interpreted as meaning 'the Very Bright', stemming from the Indo-European root "*bʰelH-" ('white, shining'; cf. Lith. "báltas" 'white', Greek φαλόσ "phalós" 'white', Arm. "bal" 'pallor', goth. "bala" 'grey') attached to the superlative suffix *-"isamā". As for "Belenos", however, this theory has come under increasing criticism in contemporary scholarship.
Xavier Delamarre notes that the proposed cognates stemming from "*bʰelH-" do not seem to connote 'shining', but rather 'white, grey, pale', and proposes to derive the name from the Gaulish root "belo"- ('strong, powerful'), hence rendering "Belesama" as 'the Very Strong' (cf. Sanskrit "baliṣṭhaḥ" 'the strongest'). Alternatively, Peter Schrijver has conjectured a connection with the root for 'henbane', *"beles"-, attached to an unknown suffix -"ma", by comparing the name with the Gaulish theonym "Belisa-maros".
The French toponyms Beleymas, Bellême, Balesmes, Blesmes, Blismes, and Velesmes are based on the theonym.
Attestations.
A Gaulish inscription found at Vaison-la-Romaine in Provence (RIG G-172) shows that a "nemeton" was dedicated to her:
The identification with Minerva in Gallo-Roman religion is established in a Latin inscription from Saint-Lizier (anciently "Consoranni"), Ariège department (CIL XIII, 8):
The presence of the goddess in Britain is more difficult to establish. Based on Ptolemy listing a "Belisama estuary", River Ribble in England seems to have been known by the name Belisama in Roman times. However, it is also said to be the name of the River Mersey.
Theories.
The attestation of the theonym as a river name may indicate that she was a lake- and river-goddess. Belisama has also been speculatively claimed as companion of Belenos, whose name seems to contain the same root.