noun.
An agreement; a compact; a convention; especially, an agreement between church and state.
noun.
Specifically— In canon law, a compact, covenant, or agreement concerning some beneficiary matter, as a resignation, permutation, promotion, or the like.
noun.
In civil law, a composition deed.
noun.
A convention or treaty between the see of Rome and any secular government, with a view to arrange ecclesiastical relations. The most celebrated modern concordat is that concluded in 1801 between Napoleon Bonaparte as first consul and Pius VII., defining. the restored privileges of the Roman Catholic Church in France, and regulating in detail the relations between the ecclesiastical and civil powers.