ergastŭlārĭus

a, um, adj.

ergastulum

I. of or belonging to a workhouse or house of correction (late Lat.).
I. Adj.: servus, Amm. 14, 11 fin.—Also: in tenebris ergastularibus, Sid. Ep. 7, 9.—
II. Subst.: ergastularii, ōrum, m. (sc. servi), overseers of a penitentiary, Col. 1, 8, 17.
Lewis & Short
A Latin Dictionary, 1879
An open-access project