1. A method in a computer system for determining the similarity of a pair of input words, the method comprising: (a) selecting a multiplicity of pairs of words known to be synonyms; (b) for a each selected pair of synonyms: (1) identifying the most salient semantic relation paths connecting the words of the pair of synonyms, each identified semantic relation path comprising an ordered series of semantic relations, each semantic relation having a relation type; and (2) for each identified path: (A) extracting from the path a path pattern comprising the relation types of the relations of the path; and (B) augmenting a path pattern frequency indicating the likelihood that an arbitrary pair of words that are connected by a path having the extracted path pattern have similar meanings; (c) identifying the most salient semantic relation paths connecting the input words; and (d) obtaining from the path pattern frequencies for the path patterns of the identified paths a quantitative measure of the similarity of the input words.