The hydronyms in Onuškis area
In total, 120 hydronyms had been registered in Onuškis Valsčius (a rural district) in 19351938, i.e., the names of 95 lakes or their parts, 25 rivers, sources, runnels or their parts.
According to the name origin, the names of Indo-European, Baltic and Lithuanian layer, as well as non-Lithuanian (Slavonic) or uncertain origin should be distinguished. The name of Lake Anykštis can be attributed to the Indo-European layer. Even 18 hydronyms belong to the Baltic layer: Dusia, Dusmena, Gaidinė, Gaidinis, Galvožeris, Gėjus, Gruožė, Gruožys, Gruožis, Lieluka, Lielukas, Solius, Solis, Solys, Spengla, Staginis, Steginis, Svitukas. Major part of hydronyms can be sufficiently explained by Lithuanian language data. Three hydronyms have been found to be formed of the Slavonic words. The analysis of origin shows that the overall majority of hydronyms are authentic and formed on the soil of Baltic and Lithuanian languages. Such hydronyms as Solius, Solis, Solys, Svitukas due to their origin and phonetic peculiarities, can be relics of the Prussian and Yotvingian languages now extinct. Moreover, new hypotheses of the origin of hydronyms Bildiškis, Drabužis, Graužinė, Graužinka, Gruožė, Gruožys, Gruožis, Samava, Samė, Samis, Solius, Solis, Solys, Staginis, Steginis, Šermis, Urmis, Verniejus have been proposed about their possible relation to the common words.
According to word formation, the hydronyms can be primary, i.e., coinciding with basic words, or secondary, i.e., formed by applying additional means. According to the type of formation the suffix type of hydronyms prevail, making 50 ones, or 42.8 per cent of all the hydronyms of obvious formation. Then, according to their frequency, follow primary hydronyms (22 derivatives, or 18.8 per cent); ending derivatives (18 ones, or 15.4 per cent); composite (16 ones, or 13.7 per cent), compound (8 hydronyms, or 6.9 per cent), and prefix derivatives (3 words, or 2.6 per cent). The trends in formation of Onuškis Valsčius hydronyms are similar to those in other areas of Lithuania, i.e., the prefix derivatives prevail, but compound derivatives in Onuškis are met significantly rarer, while primary and ending derivatives are much more numerous than in other areas.
There is very different semantics of hydronyms or motivation of their formation, but the motives met more often can be distinguished. The most names express the peculiarities of the site, dependence and channel direction, type of banks and size. In rarer cases, the hydronym semantics or motivation can be related to the names of animals (mainly fishes or wolf) as well as water colour, odour, temperature, and bottom features. There were rare cases of motivation to appear hydronyms expressing water surface or stream peculiarities or mythological reasons, and direct relation or common names of water bodies. The least frequencies of hydronyms (one for each case) were found to be metaphoric, related to plant names or expressing water body purpose.