Proved or generally recognized: the only known case; a known authority. (adjective)
Something that is known: In this instance, the only known is our actual profit margin. (noun)
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 "known" in a sentence
"The reason for the block is not known (and may never be known*), and I am not the only blogger in China who is sad (and angry) that the Chinese government feel the need to protect their citizens from diverse opinions and cultural-exchange in the name of "political stability.""
""He had known woman," Maytera Mint explained, hoping that Spider would understand what she intended by _known_."
""Can you give me a condensed report on what is known -- and I mean _known_ -- on telepathy and teleportation?""