counterforce 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 force, action, etc. that counters or checks another; specif., the use of strategic air and missile nuclear forces to destroy the nuclear striking power of the enemy, esp. as an opening action in hostilities
counterforce definition by American Heritage Dictionary
A contrary or opposing force, especially a military force capable of destroying the nuclear armaments of an enemy.