EN
1. Both the oikonym and the anoikonym Ples are explained by means of the dialectal noun 'ples' (depression in the ground of the river). The origin of this noun has not been explained clearly yet. The connection between the toponyms and the appelative enables to explain them from the root *plekt- (to plait) with the original meaning ((simple) weir made of plaited branches). This meaning has changed later - through the metonymical shift - to the meaning 'area behind the weir'. 2. Two oikonyms Plesna occuring in two different Bohemian and Moravian regions could be homonyms: the first one is connected with the noun 'pleso' (lake), the other one is supposed (on the basis of the oldest forms of this noun) to be of a different origin which is not clear: the hitherto stated motivation by the root *bliz- (near) is not probable.