interjection

1. I have found (it): believed to have been uttered by Archimedes when he discovered a way to determine the purity of gold by applying the principle of specific gravity
2. I've got it; yes; that's it: used to express triumphant achievement, success, or discovery

Etymology: 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