A system and method for enriching a concept database with homogenous concepts. The method includes determining, based on signatures of a first multimedia content element (MMCE) and signatures of a plurality of existing concepts in the concept database, at least one first concept; generating a reduced representation of the first MMCE, wherein the reduced representation excludes the signatures of the first MMCE that match the at least one first concept; comparing the reduced representation to signatures representing a plurality of second MMCEs to select a first plurality of top matching second MMCEs; generating, based on the reduced representation and the first plurality of top matching second MMCEs, at least one second concept; determining, for each second concept, whether the second concept is a homogenous concept, wherein each homogenous concept uniquely represents the same content; and adding each homogenous concept to the concept database.