We’re fortunate to include a great range of experience and interests among our membership. However, the knowledge gap between the services, generations, professionals and hobbyists can vary widely.

Click here for sources and other institutions’ glossaries.

Please note that formations may differ in size by country, service and specialism.

1SL – First Sea Lord

2iC – Second-in-Command

2Lt / 2nd Lt – Second Lieutenant

2SL – Second Sea Lord

AA – Anti-aircraft

AAA – Anti-aircraft artillery

AAC – Army Air Corps

ABM – Anti-Ballistic Missile

Adm – Admiral

AEW – Airborne Early Warning

AGC – Adjutant General’s Corps (1992-present)

Air Group – An air force unit consisting of at least two squadrons. Commanded by a Group Captain

Air Wing – An air force unit consisting at least two groups. Commanded by a Wing Commander

Art – Artillery

Battalion – A military unit consisting of 300-1,200 soldiers subdivided into a number of companies. Commanded by a Lieutenant Colonel.

Battery – An artillery unit typically consisting of six guns and their artillerymen and equipment. Equivalent of an infantry company.

BEF – British Expeditionary Force

BEM – British Empire Medal

Bn – Battalion

Brig – Brigadier

Brigade – A major tactical military unit made up of three-to-six battalions, or two regiments. Commanded by a Colonel, Brigadier, Brigadier-General or Major-General.

BRNC – Britannia Royal Naval College, Dartmouth

Btry – Battery

BW – Biological weapons/warfare

C2 – Command and control

C3I – Command, control, communications and intelligence

Capt – Captain

Cav – Cavalry

CBRN – Chemical, Biological, Radiological and Nuclear

Cdo – Commando

Cdr – Commander

Cdre – Commodore

CDS – Chief of the Defence Staff

CGS – Chief of the General Staff

CIWS – Close-in weapons system

CO – Commanding Officer

COBR – Cabinet Office Briefing Rooms

COBRA – Cabinet Office Briefing Room A

CofS – Chief of Staff

Col – Colonel

Company – A military unit made up of two or more platoons (30-250 soldiers). Commanded by a Captain or Major.

Corps – A major military unit made of two-to-five divisions (20,000-80,000 soldiers). Commanded by a Lieutenant General.

Cpl – Corporal

CQB – Close quarters battle

CSM – Company Sergeant Major

CSN – Confederate States Navy (1861-65)

CSS – Confederate States Ship

CVN – Nuclear-powered aircraft carrier

CW – Chemical weapons/warfare

DDG – Guided-missile destroyer

DERR – Duke of Edinburgh’s Royal Regiment (1959-94)

DFC – Distinguished Flying Cross

Division – A main military unit made up of multiple regiments or brigades (6,000-25,000 soldiers). Commanded by a Major General.

DoD – U.S. Department of Defense

Dragoons – Originally, mounted infantry named for their use of carbines (fire-breathing “dragons”).

DZ – Drop zone

ECM – Electronic countermeasures

EOD – Electronic Ordnance Disposal

FAA – Fleet Air Arm

FFG – Guided-missile frigate

FOB – Forward Operating Base

GCHQ – Government Communications Headquarters

GHQ – General Headquarters

GPMG – General purpose machine gun

HMG – Her/His Majesty’s Government

HMNB – Her/His Majesty’s Naval Base

HMS – Her/His Majesty’s Ship

HQ – Headquarters

Hussars – Light cavalry.

IJN – Imperial Japanese Navy (1868-1945)

Inf – Infantry

IWM – Imperial War Museum

JHC – Joint Helicopter Command

JTF – Joint Task Force

KOYLI – King’s Own Yorkshire Light Infantry (1881-1968)

Kriegsmarine – German Navy (1935-45)

LCpl – Lance Corporal

LRDG – Long Range Desert Group (1940-45)

Lt – Lieutenant

Lt Inf – Light Infantry

Luftwaffe – German Air Force (1933-46)

Maj – Major

MBT – Main Battle Tank

MC – Military Cross

MEDEVAC – Medical Evacuation

Mid – Midshipman

MM – Military Medal

MoD – Ministry of Defence

NAM – National Army Museum

NATO – North Atlantic Treaty Organisation

NCO – Non-Commissioned Officer

OiC – Officer in Command

OP – Observation Post

OpSec – Operational Security

OTC – Officer Training Corps

PJHQ – Permanent Joint Headquarters

PLA – People’s Liberation Army (China)

PLAN – People’s Liberation Army Navy (China)

PWRR – Princess of Wales’s Royal Regiment (1992-present)

QRF – Quick Reaction Force

RA – Royal Artillery

RAC – Royal Armoured Corps

RAdm – Rear Admiral

RAF – Royal Air Force (1918-present)

RE – Royal Engineers

Regiment – A military unit whose role and size varies by country and/or function. Often made up of multiple battalions. Commanded by a Lieutenant Colonel.

REME – Royal Electrical and Mechanical Engineers

RFC – Royal Flying Corps (1912-18)

RFA – Royal Field Artillery; Royal Fleet Auxiliary

RGBW – Royal Gloucestershire, Berkshire & Wiltshire Regiment (1994-2007)

RGJ – Royal Green Jackets (1966-2007)

RHA – Royal Horse Artillery

RHQ – Regimental Headquarters

RLC – Royal Logistic Corps (1993-present)

RM – Royal Marines (1664-present)

RMA – Royal Military Academy, Sandhurst

RMP – Royal Military Police (1926-present)

RMR – Royal Marines Reserve

RN – Royal Navy

RNAS – Royal Naval Air Service (1914-18); Royal Naval Air Station

RNR – Royal Naval Reserve

RoE – Rules of Engagement

RSM – Regimental Sergeant Major

RSME – Royal School of Military Engineering, Chatham

RTR – Royal Tank Regiment (1939-present)

RUC – Royal Ulster Constabulary (1922-2001)

SAM – Surface-to-Air Missile

SAR – Search and Rescue

SAS – Special Air Service (1941-present)

SBS – Special Boat Squadron (1940-present)

SeAL – Sea, Air, Land

SitRep – Situation Report

SF – Special Forces

SLR – Self-loading rifle

SMG – Sub-machine gun

SMHS – Salisbury Military History Society (2019-present)

Sqn – Squadron

Squadron (army) – A sub-unit of a cavalry, engineer or armoured regiment. Equivalent of an infantry company

Squadron (air force) – A unit consisting of three or four flights (12-24 aircraft). Commanded by a Squadron Leader or Wing Commander

STOVL – Short-Take-Off and Vertical Landing

TA – Territorial Army, the UK’s army reserve (1921-1967 and 1979-2014)

TAVR – Territorial and Army Volunteer Reserve (1967-1979)

UAS – University Air Squadron

UAV – Unmanned Aerial Vehicle

UDR – Ulster Defence Regiment (1970-92)

UN – United Nations

URNU – University Royal Naval Unit

USMC – United States Marine Corps (1798-present)

USN – United States Navy

USS – United States Ship

UW – Urban Warfare

VAdm – Vice Admiral

VC – Victoria Cross

Waffen-SS – Armed branch of the Nazi Party’s Schutzstaffel (1933-45)

Wehrmacht – German armed forces (1935-45)

Wing – An air force unit consisting at least two groups. Commanded by a Wing Commander

WMD – Weapons of Mass Destruction

WW1 – World War One (1914-18)

WW2 – World War Two (1939-45)

XO – Executive Officer

Yeomanry – Reserve cavalry