Wordnets are lexical databases in which words are organized into clusters based on their meanings, and they are linked to each other through different semantic and lexical relations. The first wordnet called Princeton WordNet has been created for English, which has been followed by various wordnets born within the framework of EuroNet and BalkaNet projects. We focuses on the development of the Wordnets and of the Hungarian WordNet (HuWN). The process of constructing HuWn is illustrated with examples, some language-specific and language-independent problems encountered during the building process are discussed, and basic statistical data on HuWN are presented as well. Finally, two subontologies of HuWN, namely, the financial domain ontology and the legal domain ontology are also presented, with applications.