A more thorough explanation:

Ecclesiastical law is a set of rules and regulations that govern the practices and beliefs of a particular church. It is derived from both canon law (the law of the church) and civil law (the law of the state) and is administered by the ecclesiastical courts.

For example, in the Anglican Church, ecclesiastical law governs the doctrine and discipline of the church. This includes rules about how services are conducted, how clergy are ordained and disciplined, and how disputes within the church are resolved.

Ecclesiastical law is also sometimes referred to as jus ecclesiasticum or law spiritual.