What is Chambers?

Legal Definition
In law, a chambers is a room or office used by barristers or a judge. A barrister's chambers or barristers' chambers are the rooms used by a barrister or a group of barristers. A judge's chambers, on the other hand, is the office of a judge, where the judge may hear certain types of cases, instead of in open court.
-- Wikipedia
Legal Definition
Practice. When a judge decides some interlocutory matter, which has arisen in the course of the cause, out of court, he is said to make such decision at his chambers. The most usual applications at chambers take place in relation to taking bail, and staying proceedings on process.
-- Bouviers Law Dictionary
Legal Definition
In practice. The private room or office of a judge; any place in which a judge hears motions, signs papers or does other business pertaining to his office, when he is not holding a session of court. Business so transacted is said to be done "in chambers." In re Neagle (C. Ct) 39 Fed. 855, 5 In R. A. 78; Von Schmidt v. Widber, 99 Cal. 511, 34 Pac. 109; Hoskins v. Baxter, 64 Minn. 226, 66 N. W. 969. The term is also applied, in England, to the private offico of a barrister. In international law. Portions of the sea cut off by lines drawn from one promontory to another, or included within lines extending from the point of one cape to the next, situate on the sea-coast of the same nation, and which are claimed by that nation as asylums for merchant vessels, and exempt from the operations of belligerents.
-- Black's Law Dictionary
Legal Definition
The personal rooms of a judge where he or she may hear matters in private.
Legal Definition
A judge’s private room apart from the courtroom.
-- Ballentine's Law Dictionary