The Timok (Serbian and , ), sometimes also known as Great Timok (, ), is a river in eastern Serbia, a right tributary of the Danube. For the last 15 km of its run it forms a border between eastern Serbia and western Bulgaria.
It is a branchy system of many shorter rivers, many of them having the same name (Timok), only clarified with adjectives. From the farthest source in the system, that of the Svrljià ¡ki Timok, until its confluence (as Veliki Timok), the Timok is 202 km long. The area of the river basin is . Its average discharge at the mouth is . The Timok Valley is known for the most important Vlach population in Eastern Serbia.
Its name stems from antiquity, in Latin it was known as Timacus and in Ancient Greek Timachos, äïüñÃÂÿÃÂ.
This in turn comes from Proto-Indo-European *tmÃÂ¥Hes-, zero-grade of *témHes-, *témHos- (âÂÂdarknessâÂÂ), an s-stem from the root *temH- (âÂÂdarkâÂÂ), also present in the names of the Thames and Tamià ¡/Temes/TimiÃÂ, possibly with extension "-q" for water (present in Latin "aqua").
The Timok, also named Veliki Timok to distinguish it from its tributaries, is formed by the confluence of the rivers Beli Timok ("White Timok") and Crni Timok ("Black Timok") at ZajeÃÂar. The Beli Timok is formed by the confluence of the rivers Svrljià ¡ki Timok ("Svrljig Timok") and Trgovià ¡ki Timok ("Trgovià ¡te Timok") at Knjaà ¾evac.
Tributaries of the Timok are Duboki Dol, Beslarica, Golami Dol, Kijevska, BraÃÂevicka, Studena Voda, Pivnica and Eleshchev from the right, and LipoviÃÂka River, Crna reka, Jelaà ¡niÃÂka reka, Salaà ¡ka reka, Ogaà ¡u Taba, BrusniÃÂki potok, UroviÃÂki potok, Plandià ¡te, and Sikolska river from the left.
The Timok turns north-west after its formation at ZajeÃÂar, running next to the villages of Vraà ¾ogrnac, Trnavac, ÃÂokonjar, and Brusnik. Passing between the last two it leaves the Timok Valley and enters the Negotin Valley.
In the lower course the Timok has no major settlements on the Serbian side (though flowing only 7 km from Negotin). Some 15 km before it empties into the Danube as its right tributary, the Timok becomes a border river, passing next to the Bulgarian town of Bregovo and the Bulgarian village of Baley. The river's mouth represents the northernmost point of Bulgaria, and is only 28 m above sea level, which makes it the lowest point of Serbia. The average discharge is 24 m<sup>3</sup>/s, but it can grow to 40 m<sup>3</sup>/s, and the Timok is part of the Black Sea drainage basin. The main (right) tributaries in this section are Crna reka, Salaà ¡ka reka, Sikolska reka and ÃÂubarska reka (Cyrillic: æÃÂýð ÃÂõúð, áðûðÃÂúð ÃÂõúð, áøúþûÃÂúð ÃÂõúð and çÃÂñðÃÂÃÂúð ÃÂõúð).
Apart from the Timok Valley, the Timok gave its name to the two tribes who lived on its banks, Thracian or Thraco-Celtic Timachi in the I to III century common era, and Slavonic TimoÃÂani in the VI to IX and to a rebellion against Serbian king Milan ObrenoviÃÂ IV in 1883, known as the Timok Rebellion.
At ÃÂokonjar, the Sokolovica power plant was constructed in 1947âÂÂ1951. Opportunities for higher electricity production are not used.
The river has been greatly ecologically damaged in recent years by the mining and heavy metal industry in Bor and Krivelj and is consequently polluting the Danube with lead, copper and cadmium.
The river valley is a natural route for the road and railway Nià ¡ - Prahovo.