A computing system has a data storage device (4, 5, 6) for storing a database consisting of a classified vocabulary of terms. A processor (1) of the apparatus is arranged to associate each term with one of a number of different categories of data and to associate all terms falling within the same category with a common code identifying a collocation of terms that exemplify that category so that terms in different categories are associated with different codes and can be disambiguated. The processor (1) is arranged to write, directly or indirectly, a classified vocabulary consisting of the terms together with the associated code onto a computer-readable storage medium (RDD2) or to supply an electrical signal via, for example a MODEM (10) or a LAN/WAN (11). The database may be used in classification of documents, spelling checking of documents and refining of keyword search results.