Dodecanese Symi, Tilos, and Kastellorizo. Other islands in the chain include Alimia, Arkoi, Chalki, Farmakonisi, Gyali, Kinaros, Levitha, Marathos, Nimos, Pserimos, Saria, Strongyli, Syrna and Telendos. The name "Dodecanese" (older form ἡ Δωδεκάνησος, "hē Dōdekanēsos"; modern τα Δωδεκάνησα, "ta Dōdekanēsa"), meaning "The Twelve Islands", denotes today an island group in the southeastern Aegean Sea, comprising fifteen major islands (Agathonisi, Astypalaia, Chalki, Kalymnos, Karpathos, Kasos, Kastellorizo, Kos, Lipsi, Leros, Nisyros, Patmos, Rhodes, Symi, and Tilos) and 93 smaller islets. Since Antiquity, these islands formed part of the group known as the "Southern Sporades" (Νότιες Σποράδες). The name "Dōdekanēsos" first appears in Byzantine
Kasos island formally joined the Kingdom of Greece on 7 March 1948 together with the other Dodecanese islands. Kasos Kasos (; , ), also Casos, is a Greek island municipality in the Dodecanese. It is the southernmost island in the Aegean Sea, and is part of the Karpathos regional unit. , its population was 1084. The island is known in Italian as "Caso". Kasos lies southwest of Karpathos, between this island and Crete. Adjacent to the island is the Strait of Kasos, through which some of the Modified Atlantic Water enters the Sea of Crete. Its shape is elliptic and resembles