Regimental sergeant major (RSM) is an appointment that may be held by warrant officers class 1 (WO1) in the British Army, the British Royal Marines and in the armies of many other Commonwealth and former Commonwealth nations, including Australia, Kenya and New Zealand. It is also an appointment that may be held by chief warrant officers (CWO) in the Canadian Forces and warrant officers of any grade in the Singapore Armed Forces, and is a rank in itself in the Irish Defence Forces and formerly in the British Army, Royal Marines and United States Army. Only one warrant officer holds the appointment of RSM in a regiment or battalion, making them the senior warrant officer; in a unit with more than one WO1, the RSM is considered to be "first amongst equals". The RSM is primarily responsible fo