What does Thybris mean in Latin?

Thybris, a proper noun, means “synonym of Tiberis (“the Tiber”)”.

What is the genitive of Thybris?

The genitive singular is Thybridis. Thybris is masculine, third declension.

In classical Latin, [ˈtʰy.brɪs]; in ecclesiastical (church) Latin, [ˈtiː.bris].

proper noun · masculinethird declension

Thybris m sg (genitive Thybridis)

Classical[ˈtʰy.brɪs]Ecclesiastical[ˈtiː.bris]

masculinepoeticsingularsynonym of Tiberis (“the Tiber”)
Sī quandō Thybrim vīcīnaque Thybridis arva / intrârō (...)If I ever shall enter the Tiber and the fields bordering on the Tiber (...).29 BCE – 19 BCE, Vergilius, Aeneis 3.500
Nunc adit Hesperiōs, Rhēnum Rhodanumque Padumque / tēque, futūre parēns, Thybri, potentis aquae.And now she reaches the Hesperian [streams], the Rhine, the Rhone, and the Po, and thee, o Tiber, destined to be the parent of a mighty stream.8 CE, Ovidius, Fasti 4.571–2

Thybris, is, v. Tiberis

I. init.

After Ancient Greek Θύβρις (Thúbris)