Siretul (sĭrĕˈtōl) [key], Ukr. Seret, river, c.450 mi (720 km) long, rising in the Carpathian Mts., W Ukraine, and flowing SE through E Romania to the Danube River at Galaţi. Its chief tributaries are the Bistriţa and Moldava rivers. Timber is floated on the river to Galaţi. It is sometimes called the Sereth River.