In this article an etymology of the Russian place name Meshchovsk, a town in the Kaluga region, is discussed. The earliest variants of this name mentioned in historical sources imply a different original form; the modern form of this toponym is a result of several consequent phonetic changes. V. A. Nikonov's etymology, explaining this name as coming from Lettish 'forest, grove', Lithuanian mikas 'forest', is inadequate from the phonetic point of view. In our opinion, the old place name originates from an unattested Slavonic hydronym. The root *mez- is rather frequent in East Slavonic river names; on the appellative level it occurs in words meaning 'the little finger (toe)', 'a youngest child', etc., and is related to Lithuanian mazas 'small', Lettish mazs, Old Prussian massais 'less' (E. Berneker, A. Brueckner and others). Thus the etymological meaning of this hydronym is 'a small stream'.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.