Having no previous example: unprecedented economic growth. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "unprecedented" in a sentence
"The word "unprecedented" really does not adequately describe the Fed's intervention to rescue financial institutions."
"House Intelligence Committee Chairman Mike Rogers praised the administration for winning what he called "unprecedented" international cooperation in going after Libya."
"Al-Jazeera also said its journalists' equipment had been stolen and destroyed during more than a week of unrest and it had faced what it called unprecedented levels of interference in its broadcast signal across the Arab world."