A Molotov Cocktail, also known as a petrol bomb, incendiary bottle etc, is a homemade incendiary grenade made from a glass bottle filled with gasoline or other flammable liquid, and a rag or other flammable object, such as a roll of paper, as a crude fuse. The name "Molotov cocktail" came from the use of the Molotov by the Finns in the Winter War or 1939-1940, where the Finns successfully used the crude weapon to destroy numerous Soviet armored vehicles in the war. The device was named after Soviet foreign minister Vyachslav Molotov, who the Finns first named Soviet cluster bombs "Molotov bread baskets" after. At some point, the Finns started referring to petrol bombs as "Molotov cocktails", as "a drink to go with the food".
Petrol bombs were used prior to the Winter War, at least as early as the Spanish Civil War, and were subsequently used by resistance movements in World War II, and by soldiers of the Red Army, who, when anti-tank grenades were not available, used molotovs or even simply climbed onto tanks and poured gasoline into the crew compartment to set fire to the vehicles. Unlike WWII-era tanks, modern tanks are highly resistant to damage from molotovs as they generally have fire supression systems, though a molotov to the crew compartment would still force the crew to evacuate the vehicle, leaving them vulnerable to attack.
While not longer an effective anti-tank weapon, molotov cocktails are still a favored weapon of rioters, criminals, militias, and resistance movements, as they are still capable of setting fire to structures and unarmored vehicles.