WordWeb

One-click English dictionary and thesaurus for Windows. Dictionary apps for mobiles, tablets and Mac desktop. In difference to Lingoes Translator you it is only a word-translator not a text-translator.

Free Mac OS X Windows Android iPhone iPad

Artha

Artha is a handy thesaurus based on WordNet with distinct features like global hotkey look-up, passive desktop notifications, regular expression based search, etc..

Free Open Source Windows Linux

WordNet

WordNet® is a large lexical database of English. Nouns, verbs, adjectives and adverbs are grouped into sets of cognitive synonyms (synsets), each expressing a distinct concept.

Free Open Source Windows Linux Web

VerbAce

VerbAce-Pro is an easy-to-use Desktop Translation Software. Translate in a mouse click From any application Access Wikipedia Quick translation option by moving the cursor

Freemium Windows Android

Moby Thesaurus

30,000 root words, 2.5 million synonyms andrelated words

Free Open Source Windows Linux

TemaTres

The open source way to manage formal representations of knowledge: Ontologies, Taxonomies, Thesauri, list of values.

Free Open Source Self-Hosted