What is "dicastery"

Dicastery \Di*cas"ter*y\, n. [Gr. ?, fr. ? juryman. See Dicast.] A court of justice; judgment hall. [R.]
--J. S. Mill.

n. 1 A term used by the Vatican corresponding to ministry or department as subdivisions of the papal curia, referring to the administrative departments of the Vatican City State, as well as strictly ecclesiastical departments; more often termed congregation. 2 A judicial body of the ancient Athenian state, made up of dicasts.

Dicastery (from Greek δικαστήριον, law-court, from δικαστής, judge/juror) is an Italicism that properly denotes the departments of the Roman Curia.