1. A computer-implemented method comprising: receiving, at a computer system, a request to classify a first query; obtaining, by the computer system, session data for the first query, wherein: the session data for the first query identifies a plurality of sessions in which the first query occurs, each session of the plurality of sessions includes (i) one or more queries submitted in succession by a single respective user for the session and (ii) one or more search entities returned in response to executing the one or more queries, and each search entity of the one or more search entities is assigned one or more classifications; selecting, by the computer system from the session data for the plurality of sessions in which the first query occurs, a first plurality of search entities, wherein the first plurality of search entities are the search entities that frequently occur in the plurality of sessions in response to executing the first query; identifying, by the computer system, one or more potential classifications for the first query; for each potential classification of the one or more potential classifications, determining a first measure of how many of the first plurality of search entities have been assigned the potential classification; determining that the first measure satisfies a classification threshold; and in response to determining that the first measure satisfies the classification threshold, assigning the respective potential classification to the first query; determining that a second query occurs in the same first session with the first query; and assigning the potential classification to the second query.