Contributions of the Thesaurus of the argentinian legal IT system to legal terminology The application of information technology to the field of law is referred to as "legal IT". Documentary legal IT is based on legal databases. These databases contain basically three types of documents, corresponding to the three main sources of law: jurisprudence, legislation and the doctrine of authors. There are public and private databases. The only public database in our country is the SISTEMA ARGENTINO DE INFORMATICA JURIDICA ("Argentinian Legal IT System"), which depends on the national Justice Ministry. At present this database has over 510.000 documents. In this brief study we shall look in particular at a linguistic tool available to users of the system which enables them to recover information by topics: the Legal Thesaurus