Assistant bishop
An assistant bishop in the Anglican Communion is a bishop appointed to assist a diocesan bishop.
Church of England
In the established Church of England, assistant bishops are usually retired (diocesan or suffragan) bishops – in which case they are honorary assistant bishops. Occasionally active bishops are appointed to be assistant bishops – however, unlike a diocesan or suffragan they do not hold a title: they are not the "Bishop of Somewhere". Some honorary assistant bishops (more frequently in the past, when Englishmen were commonly bishops in the then-colonies) are bishops who have resigned their see and returned to a priestly ministry (vicar, rector, canon, archdeacon, dean etc.) in an English diocese.
From 1987 until 2016, there were two successions of assistant bishops who were active rather than retired: the Assistant Bishop of Newcastle and the Assistant Bishop of Leicester. In practice, they acted almost exactly like a suffragan bishop (those dioceses had none), whereas they were actually stipendiary assistant bishops. Following the passage of the Bishops and Priests (Consecration and Ordination of Women) Measure 2014 by General Synod, further appointment to these roles was made untenable. Therefore, when their incumbents retired in 2016 and 2017 respectively, they were replaced with suffragan bishops: the Bishop of Berwick (a see abeyant since the 16th century) for the Diocese of Newcastle, and the Bishop of Loughborough (a newly-erected see) for the Diocese of Leicester.
Anglican Church of Australia
In the Anglican Church of Australia, the appointments of assistant bishops have been made in accordance with the Assistant Bishops' Canon since 1966.[1] In the Australian dioceses, these assistant bishops function similarly to suffragan bishops in England (the Australian church has no suffragans per se). According to the 1966 canon, while the term coadjutor bishop may be used for an assistant bishop, no bishop may have the right or expectation to succeed to a diocesan see.