An approach to the design of a system of automated construction of a general-purpose lexical ontology is proposed, and the architecture of such a system is described. Wiktionary is chosen as the online dictionary because it has a large database of words with translations into many languages. The structure of the dictionary entry is considered using the English Wiktionary as an example. This structure is used to design a database for storing the retrieved information. Ontologies are an important part of knowledge management systems. Ontologies require the development of approaches and algorithms for their construction. Lexical ontologies are constructed, and the main features of two ontology databases based on the Russian and English Wiktionaries are compared. The dynamics of numerical parameters of Wiktionaries and general-purpose lexical ontologies for 2010–2012 constructed by the authors is analyzed.