The possible Russian origin of the word sülem ’beeswarm’, which is relatively new in standard Estonian, and the dialect word kosal ’light hive for hiving bees’ is discussed. The South Estonian sülem probably starts spreading in standard Estonian since 1906; by the 1930s it has become a fully naturalized apicultural term. According to some Estonian derivation specialists the word sülem ’armful, lapful’ has been derived from the noun süli : süle ’lap’ by means of the deverbal nominal suffix -m, admitting though that such a derivative pattern must be rare indeed. This article, however, suggests that the stem of sülem may have been borrowed from an oblique case form, either dative plural or instructive plural, of the Russian noun pčela ’bee (Apis mellifica)’. The core area of sülem is South East Estonia where traditions of forest apiculture used to be strong. It may well happen that some words of one and the same semantic group cross a linguistic border together. The word kussal, kossal ’light hive made of tree bark for catching swarming bees’ is a borrowing from the Russian word kuzol, kuzov ’beehive fixable to a tree trunk; lidded wicker bag carried across the shoulder for mushrooms, berries etc.’ The borrowing of both sülem and kosal may well have been stimulated by the euphemistic usage so typical of forest apiculture.