pro·tec·tor / prəˈtektər/ • n. 1. a person who protects or defends someone or something: a passionate protector of animal rights.2. a thing that protects someone or something from injury: ear protectors.3. (chiefly Protector) hist. a regent in charge of a kingdom during the minority, absence, or incapacity of the sovereign. ∎ (also Lord Protector) the title of the head of state in England during the later period of the Commonwealth between 1653 and 1659, first Oliver Cromwell (1653–58), then his son Richard (1658–59).DERIVATIVES: pro·tec·tor·al / -rəl/ adj.pro·tec·tor·ship / -ˌship/ n.