chambers
Chiefly in in chambers: a judge's private office which is used for hearings that do not need to be held in open court.
Other meanings
Originally, a set of rooms at an Inn of Court used by one or more barristers as an office and residence; now, the office of one or more barristers in any building.
In full king's chambers: parts of the sea next to the coast of England and Wales delimited by imaginary lines connecting headlands, over which the Crown asserted exclusive jurisdiction; these have now been superseded by the concept of the territorial sea.
Where this comes from
This definition is adapted from “chambers” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.