Answer: blockhouses

AnswerCrossword Clue
BLOCKHOUSESForts made of squared timbers
blockhousesA reinforced concrete shelter used as an observation point
blockhousesA one-storied timber building with loopholes, used as a fort
blockhousesA house made of squared logs
blockhousesBLOCKHOUSE, a wooden or concrete fortification with ports or loopholes for defensive fire, observation, etc