What does Rhēnē mean in Latin?

Rhēnē, a proper noun, means “an island in the Aegean Sea, one of the Cyclades, neighbouring Delos”.

What is the genitive of Rhēnē?

The genitive singular is Rhēnēs. Rhēnē is feminine, first declension.

In classical Latin, [ˈrʰeː.neː]; in ecclesiastical (church) Latin, [ˈrɛː.ne].

proper noun · femininefirst declension

Rhēnē f sg (genitive Rhēnēs)

Classical[ˈrʰeː.neː]Ecclesiastical[ˈrɛː.ne]

an island in the Aegean Sea, one of the Cyclades, neighbouring Delos
at interius Melos, Olearos, Aegilia, Cothon, Ius, Thia, Thera, Gyaros, Hippuris, Donysa, Cythnos, Chalcis, Icaria, Cinara, Nisyros, Lebinthos, Calymnia, Syme. hae quia dispersae sunt Sporades, at Ceos, Sicinos, Siphnos, Seriphos, Rhenea, Paros, Myconos, Syros, Tenos, Naxos, Delos, Andros quia in orbem iacent Cyclades dictae.c. 43 CE, Pomponius Mela, De chorographia 2.7.11
proxima ei [scil. Delo] Rhene, quam Anticlides Celadusam vocat, item Artemiten, Celadinen.Next to this island [scil. Delos] is Rhene, which Anticlides calls by the name of Celadussa, and Callidemus, Artemite[.]77 CE – 79 CE, Plinius Maior, Naturalis Historia 4.67

Rhēnē, ēs, f., = Ῥήνη,

I. an island in the Ægean Sea, one of the Cyclades, Plin. 4, 12, 22, § 67; Mel. 2, 7.

Borrowed from Ancient Greek Ῥήνη (Rhḗnē).