A daimyo was a powerful feudal lord in Japan during the Edo period, who governed large estates and had significant autonomy. They were vassals to the shogun, the military ruler of Japan, and maintained their own armies of samurai. Daimyos played a crucial role in the political and social structure of Japan, with their influence waning after the Meiji Restoration in the late 19th century, which led to the abolition of the feudal system.