A system and method are provided for refining a user's query. An entity index, generated from a corpus of text documents, is provided. The entity index includes a set of entity structures, each including a plurality of terms. Each of the terms of an entity structure is a feature of the same entity. Entity structures can be retrieved from the entity index which match at least a portion of the user's query. Clusters of the retrieved entity structures are identified which have at least one of their terms in common. A cluster hierarchy is generated from the identified clusters in which nodes of the hierarchy are defined by one or more of the terms of the retrieved entity structures. At least a portion of the cluster hierarchy is presented to the user for facilitating refinement of the user's query through user selection of a node which, when formulated as a search, retrieves one or more responsive documents from the corpus of documents.