Definition of Rosetta Stone
an inscribed stone found near Rosetta (now called Rashid) in Egypt in1799. Its text is written in three scripts: hieroglyphic, demotic, and Greek. The deciphering of the hieroglyphs by Jean-François Champollion in 1822 led to the interpretation of many other early records of Egyptian civilization. (as noun
a Rosetta stone)
a key to some previously undecipherable mystery or unattainable knowledge:zero point energy could be the Rosetta stone of physics
