Eureka is a Greek word that is defined as "I have found it!" and is a cry of happiness or satisfaction when you find something or have an achievement.(interjection)
If you've been looking for your keys for an hour and you finally find them, this is an example of a time when you would shout "Eureka!"
See eureka in Webster's New World College Dictionary
Origin: Gr heurēka, I have found, perf. of heuriskein, to find, discover < IE base *wer-, to find, take > Arm gerem, (I) capture, OIr fūar, I have found
See eureka in American Heritage Dictionary 4
Origin: Greek heurēka, I have found (it) (supposedly exclaimed by Archimedes upon discovering how to measure the volume of an irregular solid and thereby determine the purity of a gold object)
Origin: , first person sing. perfect of heuriskein, to find.
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