dicastery
A ministry or department of the Roman Curia of the Holy See, whether administrative or ecclesiastical.
The dicastery will continue to oversee the appointment of bishops in the mission territories. … There is no longer a distinction between congregations and pontifical councils because all the Vatican’s main departments are now defined as dicasteries.
A judicial body of the ancient Athenian state, made up of dicasts.
The better cause has conquered; and there is at least this advantage to the Athenian legal system, there will be no appeal nor tedious technicalities before a "higher court." The verdict of the dicastery is final.
Where it comes from
From Ancient Greek δικαστήριον (dikastḗrion, “court, tribunal”), from δίκη (díkē, “right, custom, judgement”).
Adapted from the Wiktionary entry dicastery (CC BY-SA 4.0).