To provide an information terminal for retrieving terms during the use of various media such as books, the Internet or TV, and to perform the optimal term retrieval in response to use information media.

When electronic book n data 20an are downloaded from a book server 20 on a net N for purchase, a dictionary 20bn exclusive for the electronic book n is obtained from the server 20. When a Web home page 30a is read, a dictionary 30b exclusive for the HP is obtained from a server 30. Further, when an information program is viewed on external information equipment 50 such as a TV, a dictionary 40b exclusive for the program is obtained from a corresponding TV station server 40 according to the HP address of the program received from the equipment 50 via short-range communication. Then, the exclusive dictionaries 20bn, 30b, and 40b suitable for respective information media are given priority and selected over basic dictionaries 10c and 10f preliminarily existing in a database to perform term retrieval during the display reading of the electronic book n data, during the display reading of a Web home page, or during the viewing of the TV program.