ORithm, complexity, computability> A top-level general strategy which guides other heuristics to search fOR feasible solutions in domains where the task is hard. Metaheuristics have been most generally applied to problems classified as NP-HardORNP-Complete by the theORy of computational complexity. However, metaheuristics would also be applied to other combinatORialoptimisation problems fOR which it is known that a polynomial-time solution exists but is not practical. Examples of metaheuristics are Tabu Search, {simulated annealing}, {genetic algORithms} and {memetic algORithms}. (1997-10-30)