Emeritus (pronounced /ɨˈmɛrɨtəs/) (plural Emeriti, abbreviation emer.) is an adjective that is used in the title of a retired professor, bishop, or other professional. Emerita (/ɨˈmɛrɨtə/) is often used as the female equivalent, although avoided by purists, since phrases such as professor emerita are ungrammatical in Latin. The term is used when a person of importance in a given profession retires, so that his former rank can still be used in his title. This is particularly useful when establishing the authority of a person who might comment, lecture or write on a particular subject. The word is typically used as a postpositional adjective but can also be used as a preposition adjective. It is frequently capitalized when it forms part of a title. The word originated in the mid-18th century from Latin as the past participle of emereri meaning to "earn one's discharge by service". Emereri itself is a compound of the prefix e- (a variant of ex-) meaning "out of or from" and merēre meaning "earn". Emeritus neither implies nor denies that the person is retired from all the duties of his previous title; he or she may continue to exercise some of them.