Eureka means “I have found it” in Greek. It is an exclamation to bring out the excitement of a discovery. The word has always been used as a matter of fact in the Greek language but it became famous the world over because of the great scholar Archimedes. His proclamation on a discovery that changed the science of measurements has made the word “Eureka” universal.
According to Vitruvius, a Roman writer, Archimedes was asked by Hiero of Syracuse to assess the purity of an irregular golden crown which was gifted to him by a goldsmith. One day, while pondering over this problem, he stepped into his bath and noticed the level of the water rise. It suddenly became clear to him that the volume of the water displaced must be equal to the volume of the part of his body that was submerged. This meant that the volume of irregular objects could now be measured and calculated with precision hitherto, a complete mystery. Measurements of weight were already in use, but this discovery opened doors to the measurement of density (an important indicator of purity) and thus, led to tremendous progress in the field of science. At this enlightenment, an excited Archimedes is said to have run out of his bath, on to the street, unclad and shouting the ever so famous word “Eureka! Eureka!”
There was reason enough for this word to go international. It will always be associated with his displacement principle even though we might use it for a simple math problem! As far as the story goes, Archimedes did find out that the goldsmith was a fraud and informed Hiero.