Belisama (GaulishBelesama; epigraphicallyBηλησαμα) is aCelticgoddess. She was equated by Roman commentators withMinerva byinterpretatio romana.

The GaulishtheonymBelesama has been traditionally interpreted as meaning 'the very bright', stemming from theIndo-European root*bʰelH- ('white, shining'; cf. Lith.báltas 'white', Greek φαλόσphalós 'white', Arm.bal 'pallor', goth.bala 'grey') attached to the superlative suffix *-isamā. As forBelenos, however, this theory has come under increasing criticism in contemporary scholarship.[1][2]
Xavier Delamarre notes that the proposedcognates stemming from*bʰelH- do not seem to connote 'shining', but rather 'white, grey, pale', and proposes to derive the name from the Gaulish rootbelo- ('strong, powerful'), renderingBelesama as 'the very strong' (cf. Sanskritbaliṣṭhaḥ 'the strongest').[2] Alternatively,Peter Schrijver has conjectured a connection with the stem for 'henbane', *beles-, attached to an unknown suffix -ma, by comparing the name with the Gaulish theonymBelisa-maros. According to him, this is "formally attractive and semantically possible (if *Belesama = Lat.Minerva medica) but not supported by direct evidence".[3]
The toponymsBeleymas,Bellême,Balesmes (fromBelesma),Blesmes (fromBelesma),Blismes (fromBelisma), andVelesmes are based on the theonym.[4][2] The name also appears in various river names of Gauls and Britain, includingBelisama (River Ribble) andLe Blima (Tarn).[2][5] TheGalatian personal nameBlesamius, from an earlier *Belesamios, may also be added to the comparison.[2]

AGaulish inscription found atVaison-la-Romaine (Provence, France) commemorates the establishment of anemeton (sacred grove) in her honour.[6]
The identification with Minerva inGallo-Roman religion is established in aLatin inscription fromConsoranni (modernSaint-Lizier).[6]
The presence of the goddess inAncient Britain is more difficult to establish.Ptolemy's reference to an estuary ofBelesama (Βελεσαμα), identified with the riverRibble orMersey,[6][5] may suggest that she was a tutelary goddess of the region.[6]Ronald Hutton also postulated that the name ofSamlesbury may derive from a corruption of the theonym.[10]
According toJames MacKillop, the attestation of Belisama as a river name may indicate that she was a lake- and river-goddess.[5]
Belisama has also been speculatively claimed as companion ofBelenos, whose name appears to contain the same root.[11][6]