moot court

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A mock court where hypothetical cases are tried for the training of law students.

Wiktionary

1. n. law In law school, an activity wherein students compete by making arguments with respect to a hypothetical case, or a case that has already been decided by an actual court.
2. n. law A law school organization which organizes such competitions and prepares competitors.

GNU Webster's 1913

1. n. a mock court, such as is held by students of law for practicing the conduct of law cases.

WordNet 3.0

1. n. a mock court where law students argue hypothetical cases