A vicar (/ˈvɪkər/; Latin: vicarius) is a representative, deputy or substitute; anyone acting "in the person of" or agent for a superior (compare "vicarious" in the sense of "at second hand").
Linguistically, vicar is cognate with the English prefix "vice", similarly meaning "deputy".
In addition, in the Holy Roman Empire, a local representative of the emperor, such as an archduke, could be styled "vicar".
In the early Christian churches, bishops likewise had their vicars, such as the archdeacons and archpriests, and also the rural priest, the curate who had the cure or care of all the souls outside the episcopal cities.
A vicar capitular, who exercises authority in the place of the diocesan chapter, is a temporary ordinary of a diocese during a sede vacante period.
Most vicars, however, have ordinary power, which means that their agency is not by virtue of a delegation but is established by law.
A vicar bishop usually bears in his title the names of both his titular see (usually, a smaller town within the diocese he ministers in) and the see he is subordinate to.
Historically, parish priests in the Church of England were divided into vicars, rectors, and perpetual curates.
However, some diocesan canons do define "vicar" as the priest in charge of a mission; and "curate" is often used for assistants, being entirely analogous to the English situation.
In the Evangelical Lutheran Church in South Africa, a vicar is a person who has completed seminary training and is awaiting ordination while serving at a parish where the Diocesan Council places him or her.
Anthony Trollope's Chronicles of Barsetshire are peopled with churchmen of varying situations, from wealthy to impoverished; the income differences prompted a digression in Framley Parsonage (chapter 14) on the incomprehensible logic that made one vicar rich and another poor.