2. The information processing device according to claim 1 , wherein the relevant word generating unit has: a relevant word candidate generating unit that generates candidates of the relevant words from the first word; and a relevant word determining unit that determines the relevant word from the candidates.
5. The information processing device according to claim 2 , wherein the relevant word determining unit determines the relevant word in accordance with a number of hit searches using a candidate of the relevant words generated by the relevant word candidate generating unit as a search keyword.