What is Banc?

Legal Definition
Bench; the scat of judgment; the placo where a court permanently or regularly sits. The full bench, full court. A "sitting in banc" is a meeting of all the judges of a court, usually for the purpose of hearing arguments on demurrers, points reserved, motions for new trial, etc., as distinguished from the sitting of a single judge at the assises or at nisi prius and from trials at bar.
-- Black's Law Dictionary
Legal Definition
A bench; a meeting of all the judges.
-- Ballentine's Law Dictionary