From the same source as the verb aut “to put on (shoes):” Proto-Baltic *autlā- (with tl > kl), from Proto-Indo-European *ow- “to tie, to bind” with an extra nominalizing suffix *-tlo, used to derive names of tools or weapons relating to the action described by the original stem (i.e., the original meaning of aukla was probably “thing for binding, tying (with)”). Cognates include Lithuanian aũklas “(primitive) shoe laces,” “(primitive) shoes,” aũklė “(primitive) shoe laces,” “rope,” “sock without soles,” Old Prussian auclo ([auklo]) “bridle without bit.”