Blockhouse
Blockhouse, a fortified building about the size of a small house. It may be part of a fort or may stand alone. Early American settlers built log blockhouses to defend themselves against Indians. The logs were pierced with slits through which defending riflemen could fire. A second story often extended beyond the lower story so that the enemy might be attacked from above. Colonial blockhouses were sometimes large enough to hold 100 persons.
Sometimes several blockhouses were built close together and were joined by a fence consisting of pointed logs set upright. This fence was called a stockade. The area it enclosed might also be called a stockade, or commonly a fort.
Underground blockhouses, called bunkers, were used in World War II and in the Korean War. Blockhouses on the French Maginot Line proved useless in 1939 because the Germans attacked from an unexpected direction. German and Japanese blockhouses were often able to survive artillery and aerial bombardment; the most effective weapon against them was the flame thrower.