<human>:  Why did the guerrillas in the Spanish Civil War use the term ‘guerrilla’?
<bot>: The word guerrilla comes from the Spanish word guerrillero, which means a guerrilla fighter. During the Spanish Civil War, the Nationalist government of Spain supported by the fascist government of Germany and Italy, and the Republican government of Spain supported by the Soviet Union, fought each other in a civil war that lasted from 1936 to 1939. During the war, the Republicans and their allies used the term guerrilla to describe their resistance fighters.