Past tense and past participle of understand.
Agreed on; assumed: the understood conditions of troop withdrawal.
Not expressed in writing; implied: the understood provisos of a custody agreement.
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.