Abstract: A system and method for query expansion allows the refinement and expansion of a keyword query search by combining a key concept with semantically related concepts proposed by the system and associated with that key concept. The semantically related concepts may be grouped together in a cluster, which is then presented to the user in the form of a tooltip. Once a semantically related concept is selected from the cluster, a new search is launched. This new search may use as query terms the combination of at least part of the key concept and the selected semantically related concept to thereby expand the original search.