▁in ▁eastern ▁Roman ia ▁called ▁C ern av od ă . ▁In ▁S lav ic , ▁the ▁name ▁means ▁" black ▁water ". ▁The ▁same ▁town ▁in ▁Anti qu ity ▁was ▁known ▁as ▁ Ά ξ ί ο π α ▁( A xi op a ) ▁or ▁ Ά ξ ι ο ύ π ο λ ι ς ▁( A xi oup olis ) ▁and ▁its ▁river ▁as ▁the ▁ Ά ξ ι ος ▁( A x ios ). ▁The ▁working ▁assumption ▁is , ▁therefore , ▁that ▁A xi op a ▁means ▁" black ▁water " ▁in ▁Da cian . ▁According ▁to ▁the ▁known ▁rules ▁of ▁formation ▁of ▁IE ▁composite ▁words , ▁this ▁breaks ▁down ▁as ▁ax i ▁= ▁" black " ▁and ▁op a ▁or ▁up a ▁= ▁" water " ▁in ▁Da cian ▁( the ▁- pol is ▁element ▁is ▁ignored , ▁as ▁it ▁is ▁a ▁Greek ▁suffix ▁meaning ▁" city "). ▁The ▁assumption ▁is ▁then ▁valid ated ▁by ▁exam ining ▁cogn ate ▁pla cen ames . ▁The ▁ax i ▁element ▁is ▁valid ated ▁by ▁another ▁trib ut ary ▁of ▁the ▁Dan ube ▁called ▁the ▁Ax ios , ▁which ▁is ▁today ▁known ▁as ▁Cr na ▁re ka ▁( located ▁in ▁Republic ▁of ▁Mac ed onia ▁ ▁" black ▁river ") ▁and ▁by ▁the ▁older ▁Greek ▁name ▁for ▁the ▁Black ▁sea , ▁ Ά ξ ε ι ν ος ▁ π ό ν τ ος ▁( A xe inos ▁pont os , ▁later ▁alter ed ▁to ▁the ▁eu ph em ism ▁E