Datu is the title for chiefs, sovereign princes, and monarchs in the Visayas and Mindanao regions of the Philippines. Together with Lakan (Luzon), Apo in Central and Northern Luzon, Sultan  and Rajah, they are titles used for native royalty, and are still currently used especially in Mindanao, Sulu and Palawan. Depending upon the prestige of the sovereign royal family, the title of Datu could be equated to Royal Princes, European dukes, marquesses and counts. In big barangays, which had contacts with other southeast Asian cultures through trade, some Datus took the title Rajah or Sultan.

Direct Access Test Units (DATUs) are special PSTN phone numbers that terminate at the central office switch in a telephone company's local exchange that provide switchmen and telco technicians with a circuit for testing lines in various ways.