Ack Ack : Term used to describe anti-aircraft fire.
Adrian Helmet : French regulation helmet named after its designer.
Advanced Dressing Station : The most advanced medical post behind the Regimental Aid Post.
Aerial Torpedo : A finned mortar bomb dropped from an aircraft.
Alleyman : British slang for a German soldier.
Amiens Hut : Temporary structure of canvas on a frame used at British base camps.
ANZAC : Australian and New Zealand Army Corps.
Armed Boarding Vessel : Civilian ship armed and taken into the navy.
Armed Merchant Cruiser : Large civilian vessel armed as auxiliary cruiser.
Armlet : Cloth band worn round the arm to identify a particular duty or function.
Bangalore Torpedo : Explosive tube used to clear a path through a wire entanglement.
Bantam : Term for members of battalions between 5ft 1in and 5ft 4in.
Battery : A group of six guns or howitzers.
Battle Order : British term for reduced infantry equipment. The pack was removed and the haversack put in its place, to reduce weight and facilitate movement in action.
Battle Police : Military police deployed behind an attack to interpret stragglers.
Bellied : A term used when a tank's underside was caught upon an obstacle so high that its tracks could not grip the earth.
Big Bertha : Originally the term used to describe the German 42cm Morser but later used to to identify any German artillery.
Billy : Australian nickname for a cooking-pot or can.
Black Hand Gang : Slang for a raiding party on a difficult mission.
Blighty : British Army slang for Britain.
Blighty One : A wound bad enough for a soldier to be sent back to Britain.
Boche : French slang for German.
Bombardier : A Royal Artillery corporal.
Box Barrage : Artillery bombardment upon a small area.
Brass : High-ranking staff officers.
Bull Ring : Training-ground behind the lines where recruits could be prepared for service at the front.
Bully Beef : Canned corned beef that was the principal protein ration of the British Army.
Case-Shot : Short-range artillery anti-personnel shell filled with pellets, chain-links, etc.
Casualty Clearing Station : Main medical establishment immediately behind the front line.
Chinese Attack : Term used to describe a faked attack. When a preliminary bombardment ceased, the defending troops would return to their trenches to meet the presumed attack, whereupon the artillery would start firing again and catch the defenders out of their shelters.
Commanding Officer : In the British Army the term CO generally refired to the lieutenant-colonel in command of an infantry battalion or cavalry regiment.
Coffin-Nails : A term used by British soldiers to describe cigarettes.
Communication Trench : Narrow trench constructed at an angle to a defensive trench to permit concealed access to the trench.
Conscription : In January 1916, Parliament passed the first conscription laws (compulsory enrollment) ever passed in Britain. At first only single men and childless widowers aged 18 to 41 were called up. By 1918 compulsory service had been extended to include all men aged 18 to 51. More than 2.3 million conscripts were enlisted before the end of the war in November, 1918.
Corkscrew : Metal post for supporting a wire entanglement, with twisted base enabling it to be screwed into the ground, obviating the use of a hammer which might attack enemy fire.
Covering Party : A detachment of soldiers protecting a working-party in the front line.
Creeping Barrage : Artillery bombardment whose range was extended at timed intervals so as to avoid hitting one's own advancing troops.
Daisy Cutter : A shell with impact fuse to explode immediately on touching ground.
Derby Scheme : British system of voluntary recruitment instituted by Lord Derby just before conscription was introduced in 1916.
Ditched : A tank became ditched when the ground beneath became so soft or waterlogged as to prevent the tracks from gripping.
Dixie : British Army camp kettle.
Drum Fire : Artillery barrage fired not in salvo but by each gun in succession.
Duck-Board : Slatted wooden planking used for flooring trenches or muddy ground.
Dud : A shell that failed to explode.
Dugout : Shelter made in the wall of a trench, varying from a small area that could only accommodate one man (cubby hole), to a deep dugout, ten or more feet underground.
Dum-Dum : A soft-nosed bullet which expanded hitting causing a terrible wound.
Enfilade : To fire down a trench or at a row of men lengthways, rather than crossways.
Field Dressing : Small bag of bandages and pins carried by each man for application to small wounds.
Fire-Step : Step upon the forward face of a trench upon which men stood to fire or observe. The floor of the trench was lower so that the soldiers could walk upright without exposing their heads above the top.
Flak : Term used to describe anti-aircraft fire.
Flechette : Anti-personnel dart dropped from an aircraft.
Field Punishment Number 1 : Punishment of soldiers that involved being tied to a gun-wheel and being put on a bread and water diet.
Gearsman : Tank crew member responsible for managing the gears.
Glasshouse : Military prison or detention centre.
Greyback : British Army shirt.
Hun : Slang term for a German.
Iron Ration : Emergency ration of corned beef, tea, sugar and biscuit. Carried by all soldiers in case cut off from normal food supplies.
Kitchener's Army : Men recruited into the British Army a result of Lord Kitchener's appeal for volunteers.
Kite Balloon : Observation balloon controlled by a cable from the ground.
Kiwi : Term used to describe a New Zealander.
Leap-Frog : System of assault in which the first wave took the first objective and the second wave pass through them to take the second objective.
Lifting Barrage : An advancing bombardment.
Listening Post : Advanced post, usually in no-man's land, where soldiers tried to find out information about the enemy.
No Man's Land : The territory between the two front lines.
Old Sweat : An experienced soldier.
Over the Top : To leave the front trench and attack the enemy.
Pals Battalion : Soldiers raised in the same locality with the promise they would serve with their friends.
Panzer : A term used to describe a German tank.
Parados : The side of a trench farthest from the enemy.
Parapet : The side of the trench facing the enemy.
Pillbox : Reinforced concrete machine-gun post.
Push : A large-scale attack on enemy positions.
Register : Technical term used by gunners, meaning to locate a target by means of each gun in a battery firing ranging rounds. A forward observation officer would inform the battery of what adjustments were required in order to hit the target.
Respirator : Gas mask in which air was inhaled through a metal box of chemicals.
RFC : Royal Flying Corps. It became the RAF on 1st April 1918.
Runner : Soldier who carried messages by hand.
Russian Sap : Narrow trench dug like a mine-shaft so that the surface of the earth was not disturbed. A sap trench helped raiders to approach enemy lines without being detected.
Salient : Trench-system projecting towards the enemy.
Sandbag : Sack filled with earth from which defences were built.
Sap : Narrow trench, normally for communication, made by digging at an angle from the existing trench.
Shell-Shock : Psychological disorder caused by prolonged exposure to combat.
Shrapnel : Steel balls ejected from shell upon detonation.
Stand-To : Period when troops in the front line were required to man the firestep of their trench, fully armed, in case of enemy attack. Routinely done at dawn and nightfall when enemy attacks were most likely to occur.
Stick-Bomb : German hand-grenade with a wooden handle, so that it could be thrown further.
Tommy : Slang term for British soldier.
Tour : A period of front-line service.
Tracer : Phosphorescent machine-gun bullet which glowed in flight, indicating course as a aid to aiming.
Traverse : Trenches were not straight ditches, since this would have made them far too vulnerable to enfilade fire. Instead, they had traverses built in. These were protrusions of earth or sandbags into the trench, giving a crenelated appearance when viewed from the air. They also reduced the effect of shells when they landed in the trench.
Trench Foot : Fungal infection of the foot which could become gangrenous, caused by exposure to wet and cold.
VAD : Voluntary Aid Detachment.
WAAC : Women's Auxiliary Army Corps.
Whippet : Term used to describe any light tank.
White Star : A mixture of chlorine and phosgene gas.
WRAF : Women's Royal Air Force.
WRNS : Women's Royal Naval Service.