1) Lexical database 
WordNet is a lexical database for the English language. It groups English words into sets of synonyms called synsets, provides short definitions and usage examples, and records a number of relations among these synonym sets or their members. WordNet can thus be seen as a combination of dictionary and thesaurus. While it is accessible to human user...
[n] - any of the machine-readable lexical databases modeled after the Princeton WordNet 2. [n] - (trademark) a machine-readable lexical database organized by meanings
Princeton WordNet noun a machine-readable lexical database organized by meanings; developed at Princeton University