A dictionary data structure is described. The data structure is made up of first, second, and third tables. The first table is comprised of entries each representing a natural language term, each entry of the first table containing a term ID identifying its term. The second table is comprised of entries each representing a definition, each entry of the second containing a definition ID identifying its definition. The third table is comprised of entries each representing correspondence between a terminate definition defining the term, each entry of the third table containing term ID identifying the defined term and a definition ID identifying the defining definition. The contents of the data structure are usable to identify any definitions corresponding to a term.