Mechanized infantry in the context of "Foot soldier"

Infantry, or infantryman are a type of soldier who specialize in ground combat, typically fighting dismounted. Historically the term was used to describe foot soldiers, i.e. those who march and fight on foot. In modern usage, the term broadly encompasses a wide variety of subspecialties, including light infantry, irregular infantry, heavy infantry, mountain infantry, motorized infantry, mechanized infantry, airborne infantry, air assault infantry, and naval infantry. Other subtypes of infantry, such as line infantry and mounted infantry, were once commonplace but fell out of favor in the 19th century with the invention of more accurate and powerful weapons.

Motorized infantry is infantry that is transported by trucks or other motor vehicles. It is distinguished from mechanized infantry, which is carried in armoured personnel carriers or infantry fighting vehicles, and from light infantry, which can typically operate independently from supporting elements and vehicles for relatively long periods and may be airborne.

An infantry fighting vehicle (IFV), also known as a mechanized infantry combat vehicle (MICV), is a type of armoured fighting vehicle, light tank, and armoured personnel carrier used to carry infantry into battle and provide direct-fire support. The 1990 Treaty on Conventional Armed Forces in Europe defines an infantry fighting vehicle as "an armoured combat vehicle which is designed and equipped primarily to transport a combat infantry squad, and which is armed with an integral or organic cannon of at least 20 millimeters calibre and sometimes an antitank missile launcher". IFVs often serve both as the principal weapons system and as the mode of transport for a mechanized infantry unit.

Infantry fighting vehicles are distinct from general armored personnel carriers (APCs), which are transport vehicles armed only for self-defense and not specifically engineered to fight on their own. IFVs are designed to be more mobile than tanks and are equipped with a rapid-firing autocannon or a large conventional gun; they may include side ports for infantrymen to fire their personal weapons while on board.

A paratrooper or military parachutist is a soldier trained to conduct military operations by parachuting directly into an area of operations, usually as part of a large airborne forces unit. Traditionally paratroopers fight only as light infantry armed with small arms and light weapons, although some paratroopers can also function as artillerymen or mechanized infantry by utilizing field guns, infantry fighting vehicles and light tanks that are often used in surprise attacks to seize strategic positions behind enemy lines such as airfields, bridges and major roads.

An armoured personnel carrier (APC) is a broad type of armoured military vehicle designed to transport personnel and equipment in combat zones. Since World War I, APCs have become a very common piece of military equipment around the world.

According to the definition in the Treaty on Conventional Armed Forces in Europe, an APC is "an armoured combat vehicle which is designed and equipped to transport a combat infantry squad and which, as a rule, is armed with an integral or organic weapon of less than 20 millimetres calibre." Compared to infantry fighting vehicles (IFVs), which are also used to carry infantry into battle, APCs have less armament and are not designed to provide direct fire support in battle. Infantry units that travel in APCs are known as mechanized infantry. Some militaries also make a distinction between infantry units that use APCs and infantry units that use IFVs, with the latter being known as armoured infantry.

A submachine gun (SMG) or sub-gun is a magazine-fed automatic carbine designed to fire handgun cartridges. The term "submachine gun" was coined by John T. Thompson, the inventor of the Thompson submachine gun, to describe its design concept as an automatic firearm with notably less firepower than a machine gun (hence the prefix "sub-"). As a machine gun must fire rifle cartridges to be classified as such, submachine guns are not considered machine guns.

In the 20th century, the submachine gun was developed during World War I (1914–1918) as a close quarter offensive weapon, mainly for trench raiding. At its peak during World War II (1939–1945), millions of submachine guns were made for assault troops and auxiliaries whose doctrines emphasized close-quarter suppressive fire. New submachine gun designs appeared frequently during the Cold War, especially among special forces, commandos and mechanized infantrymen. Submachine gun usage for frontline combat decreased in the 1980s and 1990s.

The Battle of Dunkirk (french: Bataille de Dunkerque) was fought around the French port of Dunkirk (Dunkerque) during the Second World War, between the Allies and Nazi Germany. As the Allies were losing the Battle of France on the Western Front, the Battle of Dunkirk was the defence and evacuation of British and other Allied forces to Britain from 26 May to 4 June 1940.

After the Phoney War, the Battle of France began in earnest on 10 May 1940. To the east, the German Army Group B invaded the Netherlands and advanced westward. In response, the Supreme Allied Commander, French General Maurice Gamelin, initiated "Plan D" and British and French troops entered Belgium to engage the Germans in the Netherlands. French planning for war relied on the Maginot Line fortifications along the German–French border protecting the region of Lorraine but the line did not cover the Belgian border. German forces had already crossed most of the Netherlands before the French forces had arrived. Gamelin instead committed the forces under his command – three mechanized forces, the French First and Seventh Armies and the British Expeditionary Force (BEF) – to the River Dyle. On 14 May, German Army Group A burst through the Ardennes and advanced rapidly westward toward Sedan, turning northward to the English Channel, using Generalfeldmarschall Erich von Manstein's plan Sichelschnitt (under the German strategy Fall Gelb), effectively flanking the Allied forces.