eu·re·ka
eu·re·ka /yo͝oˈrēkə/
Exclamation. A cry of joy or satisfaction when one finds or discovers something.
interj.
1. (used as an exclamation of triumph at a discovery.)
2. (cap.) I have found (it): the reputed exclamation of Archimedes when he discovered a test, based on the principle of buoyancy, for the purity of gold.
Eureka effect - the sudden, unexpected realization of the solution to a problem