A- Alliance systems: When contries come together to achieve a certain goal, in this case, winning a war.
B- Blimp: Blimps, or zeppelins, were used by the Germans for reconnaissance missions mostly
C- Christmas truce: In the days before Christmas of 1914, German soldiers asked to truce (though unofficially) for the holiday season. Opposing sides then spent the day talking and exchanging pleasantries, like civil folk.
D- Disease: Spanish influenza, trench foot, and trench fever flourished in the cramped conditions of the trenches and army camps.
E- Execution: In WW1, 360 British and Commonwealth soldiers were executed for charges of desertion and cowardice, though many believe they should have been pardoned, as they were suffering from what is now called shellshock.
F- Fighter planes: WW1 was the first major conflict to use large amounts of aircraft to use for mainly recon.
G- Gas masks: Gas masks were made and introduced into warfare after the Allies were bombarded by Germany's use of poison gas in the treches.
H- Howitzer: Howitzers are short-barreled cannons, but the German howitzer "Big Bertha" was a massive howitzer used to attack Ally forts until the Allies used concrete and reinforced steel, which rendered "Big Bertha" less effective.
I- Imperialism: When Slavic terrorists killed Franz Ferdinand in an attempt to unite the Slavs against the Aus-Hun empire, a chain reaction set off that began World War 1
J- July 28th 1914: The day Austria-Hungary delcared war on Serbia
K- Kaiser Wilhelm: The last kaiser of Germany, who ruled the country during World War 1.
L- League of Nations: After the war, Woodrow Wilson started a League of Nations to protect world peace and to settle world affairs nonviolently.
M- Medicine: Medical advences in WW1 included; mobile x-ray units to treat broken bones quicker, blood transusions, and a method of setting broken bones that is still used in warzones today.
N- No man's land: The area between two opposing trenches where both sides were afraid to cross in fear of getting shot.
O- Ottoman Empire: When the Ottomans launched a surprise attack on Russia, Britain and France, along with Russia of course, declared war on them. This lead to thousands of Ottoman deaths and the death of the empire as a whole.
P- Propaganda: Both sides used porpaganda as a way to convince people to join their contries, military, or to support the war cause by donating food or buying war bonds.
Q- Q-ships: Q-ships were heavily weaponised ships with concealed weaponry to lure U-boats to the surface so the q-boat could attack.
R- Rations: Soldiers fighing in the war ate only what was inside of their daily rations, which mostly consisted of dried beef, biscuits, and hard chocolate.
S-Shell shock: Soldiers often would get shell shock as a result of fighting in the trench, but since doctors didn't know this existed, some soldiers suffering from shell shock would get excecuted.
T-Tanks: Tank warfare somewhat ineffective as it was hard to see while moving, the exhaust made a lot of noise, they were not well enough resistant to gunfire, and the inside was so hot it couldve set the fuel tank alight.
U- U Boats: German U-Boats provided a lot of troublento he Allies as they were submarienes and brandished torpedos that could sink large ships like a man can break a tree branch.
V- Victory: On November 11 1918, the war ended in a victory for the Allies.
W- Western front: The western front was the battlefield that was also the western border of Germany, Belgium, and France.
X- X-rays: X-ray technology greatly improved in WW1, allowing scientists to create a somewhat portable machine for battlefield use.
Y- Ypres: German soldiers invaded Ypres, and many battles were fought there.