The Thracian word sind(u)-
Word sind(u)-
Meaning river
Synonyms arta(s), iuras, mar, sara, strumon

Other words that might be of interest
achel- ‘water’, ala ‘current, stream’, alta ‘current, stream’, arma ‘swamp’, ars ‘to flow’, e(i)b ‘to flow’, kaba(s) ‘bog, swamp’, kalsas ‘dry, dried up’, ostas ‘river mouth’, pala ‘swamp’, opa ‘water’, krisos ‘river name’