Webster's Revised Unabridged Dictionary · 1913

Eureka

Eureka

[Greek {not transcribed} I have found, perfect indicative of {not transcribed} to find.]

The exclamation attributed to Archimedes, who is said to have cried out “Eureka! eureka!” (I have found it! I have found it!), upon suddenly discovering a method of finding out how much the gold of King Hiero's crown had been alloyed. Hence, an expression of triumph concerning a discovery.