Cognomen Triinu (Triinu 
) , in the world, is an extremely rare family name. The family name Triinu is habitual in Northern Europe, particularly Estonia, where it is a rare surname. Much more prevalently, Triinu is the forename as well as the last name.
Org, Jenas, Tubli, Esken, Ojalo, Õllek, Mäesepp, Allika, Paidla, Paabut, Peegel, Prants, Thaumi, Mikiver, Ausmees, Linhein, Jaakson, Toomsalu, Kivilaan, Palmiste, Pokkinen, Pääsik, Perve, Tammearu, Kruus, Koidu, Mets, Saar, Sepp, Aasa, Karu, Kask, Prii, Ruul, Lamp, Lepa, Lepp, Liis, Tamm, Tulk, Erik, Hein, Olen, Musii, Salus, Sõber, Clark, Kiska, and Hausenberg