Department of Defence (Australia) in the context of "Australian Defence Force"

The Australian Army is the principal land warfare force of Australia. It is a part of the Australian Defence Force (ADF), along with the Royal Australian Navy and the Royal Australian Air Force. The Army is commanded by the Chief of Army (CA), who is subordinate to the Chief of the Defence Force (CDF) who commands the ADF. The Department of Defence supports the ADF and the Army.

The Australian Army was formed in 1901 as the Commonwealth Military Forces, through the amalgamation of the colonial forces of Australia following the Federation of Australia. Although Australian soldiers have been involved in a number of minor and major conflicts throughout Australia's history, only during the Second World War has Australian territory come under direct attack.

The Royal Australian Navy (RAN) is the naval branch of the Australian Defence Force (ADF). The professional head of the RAN is Chief of Navy (CN) Vice Admiral Mark Hammond. The Chief of Navy is also jointly responsible to the Minister for Defence (MINDEF) and the Chief of the Defence Force (CDF). The Department of Defence, which is a part of the Australian Public Service, supports the ADF, and ergo, the Royal Australian Navy.

The navy was formed in 1901 as the Commonwealth Naval Forces (CNF) through the amalgamation of the colonial navies of Australia following the federation of Australia. Although it was originally intended for local defence, it became increasingly responsible for regional defence as the British Empire started to diminish its influence in the South Pacific.

The Australian Signals Directorate (ASD), formerly the Defence Signals Directorate, is a statutory agency of the Government of Australia responsible for signals intelligence, providing intelligence support to Australian military operations, conducting cyberwarfare and ensuring information security. The ASD is a part of the larger Australian Intelligence Community, and its role within the so-called Five Eyes intelligence-sharing alliance is to monitor signals intelligence in South and East Asia. The Australian Cyber Security Centre (ACSC) is an agency within the ASD.

The unit was established in 1947 by executive order as the Defence Signals Bureau within the Department of Defence, and underwent several name changes until its current name ASD was adopted in 2013. ASD was converted to a statutory body by the Intelligence Services Act 2001. ASD is based in Canberra, at the Defence Department Headquarters at Russell Offices. As of February 2020, Rachel Noble is the Director-General of ASD, replacing Mike Burgess, who was appointed Director-General of Security in September 2019.

The Royal Australian Air Force (RAAF) is the principal aerial warfare force of Australia, a part of the Australian Defence Force (ADF) along with the Royal Australian Navy and the Australian Army. Constitutionally the governor-general of Australia is the de jure commander-in-chief of the Australian Defence Force. The Royal Australian Air Force is commanded by the Chief of Air Force (CAF), who is subordinate to the Chief of the Defence Force (CDF). The CAF is also directly responsible to the Minister for Defence, with the Department of Defence administering the ADF and the Air Force.

Formed in March 1921, as the Australian Air Force, through the separation of the Australian Air Corps from the Army in January 1920, which in turn amalgamated the separate aerial services of both the Army and Navy. It directly continues the traditions of the Australian Flying Corps (AFC), the aviation corps of the Army that fought in the First World War and that was formed on 22 October 1912.