1. A method for information search, comprising the steps of: generating one or more semantic index key terms each including at least one semantic index token representing a semantic relationship, comprising: selecting a word and at least one further word that is linguistically related to the word from one or more references to information passages; determining information regarding use of the word and the further word within at least one of the references comprising one or more of a part of speech and a grammatical role of the word or the further word; and concatenating each of the word and the further word with the respective information into a single string as the semantic index key terms; associating each of the semantic index key terms with the at least one reference; and generating an inverted index comprising the semantic index key terms indexed against the at least one reference to each associated information passage, wherein the steps are performed on a suitably programmed computer.