In all likelihood the current name comes from a gradual evolution of `` Atax '' given by Strabo ( in his `` Geography '' , Book IV ) , a word borrowed from the Gallic term `` atacos '' meaning `` spirited '' or `` very fast '' . Geography .
In all likelihood the current name comes from gradual changes of `` Atax '' , a word borrowed from the Celtic `` atacos '' meaning `` spirited '' or `` very fast '' Geography .