In some cases, the term is conferred automatically upon all persons who retire at a given rank, but in others, it remains a mark of distinguished service, awarded to only a few on retirement. It is also used when a person of distinction in a profession retires or hands over the position, enabling their former rank to be retained in their title, e.g., "Professor Emeritus". The term emeritus does not necessarily signify that a person has relinquished all the duties of their former position, and they may continue to exercise some of them.
Emerere is a compound of the Latin prefix e- (a variant of ex-) meaning "out of, from" and merere meaning "earn"; emeritus is the past participle of the verb. The female equivalent, emerita (), is also sometimes used, but as is often true of loanwords, the use of the donor language's inflectional system faces limits in the recipient language; in English, emeritus is often unmarked for gender.
In the United States, a fully tenured professor who retires from an educational institution in good standing may be given the title "professor emeritus" regardless of gender. The title "professor emerita" is sometimes used for women. In most systems and institutions, the rank is bestowed on all professors who have retired in good standing, while at others, it needs a special act or vote. Professors emeriti may, depending on local circumstances, retain office space or other privileges. The word is used either as a postpositional adjective (e.g., "professor emeritus", Noam Chomsky, the renowned scholar and MIT professor emeritus), or as a prepositional adjective (e.g., "emeritus professor"). The concept has in some places been expanded to include tenured associate professors or non-tenure-track faculty.
In the United Kingdom and most other parts of the world, the term "emeritus professor" is given only to a person of outstanding merit who had full professorial status before he or she retired. The possession of a PhD or other higher degree, or even full professorial status, is not sufficient for calling oneself "emeritus professor" upon retirement. The term "Professor Emeritus" is also recognised in the United Kingdom. The word is capitalized when it forms part of a title which is capitalized. Oxbridge colleges may appoint distinguished fellows who have retired as "Emeritus Fellow".
When a diocesan bishop or auxiliary bishop retires, the word emeritus is added to his former title, i.e., "Archbishop Emeritus of ...", "Bishop Emeritus of ...", or "Auxiliary Bishop Emeritus of ..." Examples of usage are: "The Most Reverend (or Right Reverend) John Jones, Bishop Emeritus of Anytown"; and "His Eminence Cardinal James Smith, Archbishop Emeritus of Anycity". The term "Bishop Emeritus" of a particular see can apply to several people, if the first lives long enough. The sees listed in the 2007 Annuario Pontificio as having more than one (Arch)Bishop Emeritus included Zárate-Campana, Villavicencio, Versailles, and Uruguaiana. There were even three Archbishops Emeriti of Taipei. The same suffix was applied to the Bishop of Rome, Pope Emeritus Benedict XVI, on his retirement. In the Roman Catholic Church the word emeritus does not imply that the person in question is no longer a priest.
Since 2001, the honorary title of president pro tempore emeritus has been given to a Senator of the minority party who has previously served as president pro tempore of the United States Senate. The position has been held by Strom Thurmond (R-South Carolina) (2001-2003), Robert Byrd (D-West Virginia) (2003-2007), Ted Stevens (R-Alaska) (2007-2009), and Patrick Leahy (D-Vermont) (2015-present).
It is also commonly used in business and nonprofit organizations to denote perpetual status of the founder of an organization or individuals who moved the organization to new heights as a former key member on the board of directors (e.g., chairman emeritus; director emeritus; president of the board emeritus).
In Community of Christ, the status of emeritus is occasionally granted to senior officials upon retirement. In 1938, Frederick A. Smith was given the title of "president emeritus" of the Order of Evangelists (one of the presiding councils of the church), though the president of that body at that time was more commonly known as Presiding Patriarch. Roy A. Cheville became Presiding Patriarch Emeritus in 1974. W. Wallace Smith became the first person to retire as President of the Church (all prior presidents having served until death), and was accorded the title President Emeritus in 1978. His successor, Wallace B. Smith, was also given the title of President Emeritus, upon his own retirement in 1996. He continues to hold that status to this day.