Ratu is an Indonesian female name meaning “queen” derived from the Indonesian, Javanese, and Malay word. It’s also used as a male Fijian title for a monarch (such as a king) or chief (Adi is the female equivalent in Fijian). I don’t believe it’s used as a given name in Fiji but I am not one hundred percent sure of that. Both derive from the same Proto-Austronesian source, *datu (king).
Meaning: “queen” in Indonesian and Javanese; also used as a male title for a monarch or chief in Fiji