opposite number definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a person with reference to another having a comparable position, rank, etc. but in a different place, organization, or situation
opposite number definition by American Heritage Dictionary
A person who holds a position in an organization or system corresponding to that of a person in another organization or system; a counterpart: “had a face-to-face . . . conference with his opposite number at the American Embassy” (Frederick Forsyth).