eureka
From Longman Dictionary of Contemporary Englisheurekaeu‧re‧ka /jʊˈriːkə/ interjection humorous HAPPYused to show how happy you are that you have discovered the answer to a problem, found something etcOrigin eureka (1600-1700) Greek heureka “I have found”, said by the Greek scientist Archimedes when he discovered a method of testing the purity of gold