n. a key to previously unattainable understanding. [a stone found near Rosetta in Egypt, with a trilingual inscription of the 2nd c. BC in Egyptian hieroglyphs, demotic, and Greek, important in the decipherment of hieroglyphs]
ROSETTA STONE
Meaning of ROSETTA STONE in English
English main colloquial, spoken dictionary. Английский основной разговорный словарь. 2012