Wordnet 3.0
NOUN (1)
1.
a part of an inscribed granite stela that was originally about six feet tall and was set up in 196 BC;
the inscriptions in hieroglyphics and Demotic and Greek gave the first clues to the decipherment of Egyptian hieroglyphics;
The Collaborative International Dictionary of English v.0.48:
Ro-setta stone \Ro-set"ta stone`\
A stone found at Rosetta, in Egypt, bearing a trilingual
inscription, by aid of which, with other inscriptions, a key
was obtained to the hieroglyphics of ancient Egypt. --Brande
& C.
[1913 Webster]
WordNet (r) 3.0 (2006):
Rosetta Stone
n 1: a part of an inscribed granite stela that was originally
about six feet tall and was set up in 196 BC; the
inscriptions in hieroglyphics and Demotic and Greek gave
the first clues to the decipherment of Egyptian
hieroglyphics