A wordnet is a lexical database. It groups synonymous words into sets, the synsets, which represent distinct concepts. These synsets form nodes in a network, which are interlinked through edges that correspond to semantic relations between those synsets. For instance, the hypernym relation, also known as the "is-a" relation, that holds between the synset "{cat, true cat}" and the synset "{feline, felid}" represents that "cat" is a type of "feline".

The hypernym relation, and its symmetrical hyponym relation, are the most frequent relations found in wordnets, but wordnets go beyond this to also record relations such as meronymy (part-whole) relation, antonymy, etc.

The Princeton WordNet for English (https://wordnet.princeton.edu/) was the pioneering wordnet, and over the years many other wordnets adopted the same design principles, MWN.PT being one.

The MWN.PT WordNet for Portuguese includes over 41,000 concepts, expressed by 38,000 lexical units. Its synsets were manually validated and are linked to semantically equivalent synsets of the Princeton WordNet of English, and thus transitively to the many wordnets for other languages that are also linked to this English wordnet.