1. A server comprising: an input storage unit for storing input information containing location information indicating a geographical location, a word assigned to the location, and a user ID identifying a user having assigned the word to the location, the location information, the word, and the user ID being in association with one another; a determination unit for reading out first input information indicating first locations to which a first word is assigned by a first user and second input information indicating second locations to which a second word is assigned by a second user from the input storage unit, the first word being different from the second word and the first user being different from the second user, and determining whether a number of common locations overlapping between the first and second locations is equal to or greater than a first preset threshold based on the first and second input information; and a registration unit for creating dictionary data containing the first and second words in association with each other and entering the dictionary data into a dictionary storage unit when the determination unit determines that the number of common locations overlapping between the first and second locations is equal to or greater than the first preset threshold.