Regimental sergeant major (RSM) is an appointment held by warrant officers class 1 (WO1) in the British Army, the British Royal Marines and in the armies of many Commonwealth and former Commonwealth nations, including Ireland, Australia and New Zealand; and by chief warrant officers (CWO) in the Canadian Forces. Only one WO1/CWO holds the appointment of RSM in a regiment or battalion, making him the senior warrant officer; in a unit with more than one WO1, the RSM is considered to be "first amongst equals".