Where does “Sinae” come from?

Sinae (Late Latin) comes from Ancient Greek Σῖναι, from Arabic صِين, from Pahlavi čīn, from Sanskrit चीन, from Old Chinese 秦 — {{w|Qin |State of Qin}}, {{w|Qin dynasty}}; Qin.

Sinae (Late Latin): the southern Chinese; the Chinese; China, the...