Daimyo is a generic term referring to the powerful territorial lords in premodern Japan who ruled most of the country from their vast, hereditary land holdings. In the term, "dai" literally means "large", and "myō" stands for myōden, meaning private land.
Subordinate only to the shogun (head of the military, nominally appointed by the emperor but de facto ruler of Japan), daimyo were the most powerful feudal rulers from the 10th century to the middle 19th century in Japan.
From the shugo of the Muromachi period through the Sengoku to the daimyo of the Edo period, the rank had a long and varied history.
The term "daimyo" is also sometimes used to refer to the leading figures of such clans, also called 'lord". It was usually, though not exclusively, from these warlords that a shogun arose or a regent was chosen.