Who is the head of a Roman Catholic diocese?

The head of a Roman Catholic diocese is a bishop. The role of the bishop includes overseeing the spiritual and administrative needs of the diocese, which consists of a group of parishes. Bishops are responsible for the pastoral care and spiritual leadership in their dioceses, ensuring that the teachings and practices of the Catholic Church are upheld. They have the authority to ordain priests, confirm congregants, and administer other sacraments, making them pivotal figures within the Church's hierarchy.

In contrast, a rabbi is a Jewish leader and teacher, a priest typically serves within a specific parish or local church and does not have the broader responsibilities of overseeing multiple congregations, while a cantor is a specialist in Jewish liturgical music and also does not hold the administrative authority of a bishop. Each of these other roles is significant within their respective religious contexts, but they do not hold the ecclesiastical authority or governance of a diocese like a bishop does.