Most distant in degree, time, or space: That's the furthest thing from my mind. They explored the furthest reaches of space.
To the greatest extent or degree: went the furthest of all the children in her education.
At or to the most distant point in space or time: He swam the furthest.
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.