1. A computer-readable, non-transitory medium storing a program which, when executed by a computer, causes the computer to perform a character string comparison process, the process comprising: splitting a first character string and a second character string into words; acquiring information including a semantic attribute that represents a semantic nature of each of the words and a conceptual code that semantically identifies said each of the words, from a storage device; identifying a pair of the words having a common semantic attribute between the first character string and the second character string; comparing the conceptual codes of the specified pair of the words between the first character string and the second character string; and generating a comparison result between the first character string and the second character string based upon a comparison result of the conceptual codes.