exchange rate

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A rate of exchange.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun economics, finance The amount of one currency that a person or institution defines as equivalent to another when either buying or selling it at any particular moment
• noun economics, finance The rate at which one currency can be exchanged for another, usually expressed as the value of the one in terms of the other.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the charge for exchanging currency of one country for currency of another