The historical term abbot is used to denote the head of a religious community of men.
While several large religious institutes, for example, the Benedictines, have preserved the title, others, such as the Dominicans and Jesuits, use other terms (prior and rector, respectively) to describe the same office.
Most abbots are not bishops, but over the centuries canon law and tradition have accorded them several quasi-episcopal powers, especially in the matters of governance and worship within their community.
Dating back to the sixth century, the title “Abbess” is the feminine form of “abbot” and designates the spiritual and temporal superior elected by a community of nuns. (8:35)