| A | B |
|---|
| Mobilization | Getting a country ready for war |
| U-Boat | A boat that can travel under water |
| Machine Gun | Mechanical gun that could fire many bullets very quickly |
| Hand Grenade | Hand-held explosive that could be thrown at the enemy |
| Tank | Armored vehicle that carried large guns |
| Warfare | The way in which a war is fought |
| Trench Warfare | Soldiers hid in ditches ("trenches") while they fired on the enemy |
| No Man's Land | The open area between the trenches of the Central Powers and the Allies |
| Mustard Gas | A poisonous gas that burned and suffocated its victims |
| American Expeditionary Force | The United States armed forces sent to Europe during World War I |
