A powerful set of features can assist software developers in searching source code. Source code can be queried to find occurrences of source code elements mapped to domain concepts appearing in an ontology. Queries can specify a search for occurrences of particular operations performed on domain concepts within the source code. Query expansion can be used to locate related domain concepts as indicated in the ontology. Query keyword weighting can be used to emphasize one domain concept over another. Tools can be provided to create the ontology and associate the ontology with the elements appearing in the source code. Results can include user interface features assisting in navigation to a location within the source code associated with the query results.