general staff

noun (used with a singular or plural verb) Military.
  1. a group of officers who are without command and whose duty is to assist high commanders in planning and carrying out orders in peace and war.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for general staff

general staff

noun
  1. officers assigned to advise commanders in the planning and execution of military operations
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012