An alternative etymology connects the name to a reconstructed form *gra-snó- (< *gwhr-snó-), which could be related to Proto-Celtic *gwrīns-/gwrens-, meaning 'heat' (cf. Middle Irish grīs 'heat, glow, embers', Middle Welsh gwres 'heat [of the sun, fire], passion, lust'). Scholar Jürgen Zeidler contends that this would be a "probable reference to the sun's heat and its healing properties". In early twentieth century scholarship, the theonym was often compared with the Old Irish grían ('sun'), which, according to linguist Ranko Matasović, should be derived from Proto-Celtic *gwrensā (> Primitive Irish *gwrēnā).
An alternative etymology connects the name to a reconstructed form *gra-snó- (< *gwhr-snó-), which could be related to Proto-Celtic *gwrīns-/gwrens-, meaning 'heat' (cf. Middle Irish grīs 'heat, glow, embers', Middle Welsh gwres 'heat [of the sun, fire], passion, lust'). Scholar Jürgen Zeidler contends that this would be a "probable reference to the sun's heat and its healing properties". In early twentieth century scholarship, the theonym was often compared with the Old Irish grían ('sun'), which, according to linguist Ranko Matasović, should be derived from Proto-Celtic *gwrensā (> Primitive Irish *gwrēnā).