The paper examines the multifunctionality of the word-formation suffixes used in the formation of Old and Middle Czech deverbal nouns and the possibility of using semantic maps to analyze this multifunctionality. This methodology is first briefly introduced, then a semantic map of six onomasiological categories used in the word-formation patterns is presented (based on extensive data from Old and Middle Czech dictionaries and lexical databases), showing which combinations of functions are possible in a single suffix and which are not. The map is compared with maps found in the literature and several methodological issues are discussed.