San Piyu X, Piyu Tunkani, Giuseppe Melchiorre Sarto (latin aru: Pius PP. X, Italya aru: Papa Pio X, Kastilla aru: Papa Pío X, (* Treviso, 1835 mara 2 uru Juyphi phaxsin yuritayna - † Roma, 1914 mara 20 uru Thaya phaxsin yuriwi), Italiya jach'a marka taytakura jaqi.