n. 1. a person or thing that protects; defender; guardian. 2. (cap.) Also called Lord Protector. the title of the head of the government during the British Protectorate, held by Oliver Cromwell (1653–58) and by Richard Cromwell (1658–59).[1325–75; Middle English protectour (< Anglo-French) < Late Latin]pro•tec′tor•ship`,n. EncyclopediaSeeprotector