Reformulating query terms in structured search

Search history data such as browse trails are collected over time. The browse trails, including associated queries and domains, are processed to identify free tokens of the queries that are also modifiers. Attribute value pairs of a structured data source that correspond to the modifiers are determined based on the search history data and a frequency of the attribute value pairs in the structured data source. When a subsequent query is received, modifiers in the query are identified and replaced with the determined combinations of attribute value pairs that correspond to the modifiers in a structured query that is generated from the received query. The structured query is used to identify items and/or services in the structured data source that are responsive to the received query.