What does Bēris mean in Latin?

Bēris, a proper noun, means “a river in Pontus, mentioned by Arrian”.

What is the genitive of Bēris?

The genitive singular is Bēris. Bēris is masculine, third declension.

In classical Latin, [ˈbeː.rɪs]; in ecclesiastical (church) Latin, [ˈbɛː.ris].

proper noun · masculinethird declension

Bēris m sg (genitive Bēris)

Classical[ˈbeː.rɪs]Ecclesiastical[ˈbɛː.ris]

a river in Pontus, mentioned by Arrian
Greek text: [Ἀπὸ δὲ Θερμώδοντος ποταμοῦ] εἰς Βῆριν ποταμὸν στάδια ξʹ, μίλια ηʹ. Ἀπὸ δὲ Βήρεως ποταμοῦ εἰ Θοάριον ποταμὸν στάδια Ϟʹ μίλια ιβʹ. Latin translation: A Thermodonte ad Berin fluvium stadia 60, milia 8. A Beri fluvio ad Thoarium (Thoarin?) fluvium stadia 90, milia 121855, Karl Müller (translator), Periplus Ponti Euxini, in Geographi graeci minores, Volume 1, page 409

Borrowed from Ancient Greek Βῆρις (Bêris).