Βαῖτις

Wikipedia EN

The modern name of Guadalquivir comes from the Arabic al-wādī l-kabīr (اَلْوَادِي الْكَبِيرْ), meaning "the big river". There was a variety of names for the Guadalquivir in Classical and pre-Classical times. According to Titus Livius (Livy), The History of Rome, Book 28, the native people of Tartessians or Turdetanians called the river by two names: Certis (Kertis) and Rherkēs (Ῥέρκης). Greek geographers sometimes called it "the river of Tartessos", after the city of that name. The Romans called it by the name Baetis (which was the basis for name of the province of Hispania Baetica).

Spanish (DGE)

-ιος
• Alolema(s): lat. Baetis Liu.28.22.1, Mela 3.5
• Morfología: [gen. -ιδος Str.3.5.3]
Betis
1 ὁ Β. río de la Bética, actual Guadalquivir, Artem.Eph.Geog.21, Str.3.1.6, Plu.Cat.Ma.10, Sert.8, Ptol.Geog.1.12.10, 14.9, Paus.6.19.3, Marcian.Peripl.2.9, llamado Πέρκης por los nativos según St.Byz.s.u. Βαῖτις.
2 ἡ Β. ciudad de la Bética, dud. si actual Triana (Sevilla), Str.3.2.1.

French (Bailly abrégé)

ιος (ὁ) :
le Bétis (auj. Guadalquivir), fl. d'Espagne.