En Banc

French, meaning "on the bench." All judges of an appellate court sitting together to hear a case, as opposed to the routine disposition by panels of three judges. In the Ninth Circuit, an en banc panel consists of 11 randomly selected judges.

Additional Sources

Answers.com

Full bench. Refers to a session where the entire membership of the court will participate in the decision rather than the regular quorum. In other countries, it is common for a court to have more members than are usually necessary to hear an appeal. In the United States, the Circuit Courts of Appeal usually sit in panels of judges but for important cases may expand the bench to a larger number, when the judges are said to be sitting en banc. Similarly, only one of the judges of the U.S. Tax Court will typically hear and decide on a tax controversy. However, when the issues involved are unusually novel or of wide impact, the case will be heard and decided by the full court sitting en banc.

FindLaw

With all judges or a quorum of judges present : in full court

Law.com Dictionary

French for "in the bench," it signifies a decision by the full court of all the appeals judges in jurisdictions where there is more than one three- or four-judge panel. The larger number sit in judgment when the court feels there is a particularly significant issue at stake or when requested by one or both parties to the case and agreed to by the court.

Lect Law Library

Fr. "by the full court" "in the bench" or "full bench." When all the members of an appellate court hear an argument, they are sitting en banc. Refers to court sessions with the entire membership of a court participating rather than the usual quorum. U.S. courts of appeals usually sit in panels of three judges, but may expand to a larger number in certain cases. They are then said to be sitting en banc.

Merriam Webster

In full court : with full judiciary authority

Wikipedia

En banc, in banc, in banco or in bank is a French term (meaning "on a bench") used to refer to the hearing of a legal case where all judges of a court will hear the case (an entire "bench"), rather than a panel of them. It is often used for unusually complex cases or cases considered of unusual significance. Appellate courts in the United States sometimes grant rehearing en banc to reconsider a decision of a panel of the court (a panel generally consisting of only three judges) where the case concerns a matter of exceptional public importance or the panel's decision appears to conflict with a prior decision of the court. In rarer instances, an appellate court will order hearing en banc as an initial matter, instead of the panel hearing it first.

Some appellate courts, such as the Supreme Court of the United States and the highest courts of most U.S. states, do not sit in panels, but hear substantially all of their cases en banc (with the exception of cases where a judge is ill or recused).