The Rosetta stone had just been discovered, but nobody could make use of it yet.

And after 2,000 years, you'd be bigger than the Rosetta stone.

I need an opening, a Rosetta stone, after which all should be instantly clear.

We may never find out where or how he got it, but that ring was the Rosetta stone for cancer.

"Like a sort of Rosetta stone; do you know what that is?"

The message is too short to qualify as a Rosetta stone.

Rosetta Stone, the makers of foreign language learning software, wants to go much further.

That remains a very big secret, a buried Rosetta stone.

Bonnie's eyes got big and he slapped his hands on the table again as if he'd just found the Rosetta stone.

Or maybe it was simply that she lacked a mental Rosetta stone.