Query suggestions are generated based on a Breadth-First-Search having a configurable decaying radius. A computer system receives an initial set of semantically similar queries. The computer system expands the set to include related terms. The set of related terms is included in the initial set. The expansion process is repeated for each query or related term in the set. The radius may be reduced for each subsequent related term added to the query. The process may stop when the radius reaches a specified threshold, e.g., a predetermined number of queries or terms for the set is reached. The set includes the related terms and search queries. The set may be used for, among other things, suggesting related terms to a researcher, improving search engine performance, or selecting appropriate advertisements.