In Estonian manifestations of strabismus are referred to by nouns and adverbs of the stem kõõr-, both in standard Estonian and in dialects. Earlier the origin of the stem has been associated with the adjective kõver ’curved’, which motivation is, however, hardly plausible either phonetically or semantically. An alternative solution emerges from an analysis of Estonian dialect words on the stem kõõr- and their possible equivalents in cognate languages. In Estonian dialects the noun kõõr occurs with final -a, -e,-i or -u in vocalic stem, referring to various circular or arched objects, e.g. ’wheel hoop’, ’loom weight’, ’circular knitting motif’, ’cord decoration with loops’. A Livonian noun of the same shape stands for ’wheel’ and ’circle’, while the verb means ’to circle’, and also ’disapprove’. In Finnish dialects, the most widespread words for a squint derive from kiero ’twisted etc’, which is semantically analogous to the Livonian word. As a result of the analysis we can say that the Estonian words deriving from the base kõõr- and kõõrd- can be regarded as back-vowel equivalents of words on keer- and keerd-, which isproved phonetically, morphologically and semantically. Etymologically, both stems can be associated with the Finnish kiero/kierä word family and its stem variants in other Finnic languages.