What is Bill Of Privilege?

Legal Definition
Eng. law. A process issued out of the court against an attorney, who is privileged from arrest, instead of process demanding bail. 3 Bl. Com. 289.
-- Bouviers Law Dictionary
Legal Definition
In old English law. A method of proceeding against attorneys and officers of the court not liable to arrest. 3 Bl. Comm. 289.
-- Black's Law Dictionary
Legal Definition
A special form of action against attorneys and other court officers exempt from arrest.
-- Ballentine's Law Dictionary