Historical and differential principle of the regional vocabulary of the 17th century

The article develops criteria that should form the basis of historical and differential principle of compiling a regional dictionary of the 17th century. The principle of selection of all-Russian words, which are preserved in modern Russian with stylistic marks, adopted by lexicographers is considered methodologically unacceptable for a dictionary of this type. The glossary should include, firstly, words that were in common use in the Russian language only in the 17th century, and in the subsequent centuries they had been unknown or were in the process of emerging, and, secondly, the actual regional vocabulary of that period. We give the characteristics of the classes of words included in the regional dictionary of common vocabulary: these are words that reveal a kind of lexical and grammatical compatibility; word variants reflecting the features of the regional dialect system at different language levels; words, which have a certain area of distribution according to the illustrative material of the Russian dictionary of the 11th- 17th centuries, etc.