Dictionaries of Economics in the broad sense of the word have existed in the European context for more than 300 years. The article shows how these dictionaries have been extremely flexible in their adaptation to the complex and ever changing needs of their users. The great differences in terms of name, size, content, style, and structure may, at least partially, be explained by this fact. In this respect, the article systematizes the functions registered in economic dictionaries during the past 300 years, and presents some suggestions for the immediate future of online dictionaries.