A method and a system are described for generation of sets of alternative terms based on queries received from users. For example, a query module may receive a query comprising syntax indicating alternative terms and may parse the alternative terms from the query. A frequency module forms groups of alternative terms from the parsed alternative terms and determines a first number of occurrences corresponding to each of the groups based on the received query and previous queries. For a first pair of the groups comprising a first alternative term and a second alternative term, a threshold module adds the first alternative term to an existing set of terms that already includes the second alternative term. The addition is based on a second number of occurrences of the first alternative and at least one other member of the existing set of terms.