What is Special Jury?

Legal Definition
A special jury, which is a jury selected from a special roll of persons with a restrictive qualification, could be used for civil or criminal cases, although in criminal cases only for misdemeanours such as seditious libel. The party opting for a special jury was charged a fee, which was 12 guineas just prior to abolition in England.

The qualifications to be a special juror in England were governed by the Juries Act 1870, and the main difference between the special jury and a common jury under that Act was merely a matter of wealth; indeed, it was little more than a question of whether a person lived in a larger house, because it was mainly a question of the rateable value of the house. A householder rated at £100 in a large town, or £50 in a small town, was qualified to be a special juror, while a householder rated at £30 in London and Middlesex, and £20 elsewhere, was qualified to be a common juror. There were various other qualifications for a special juror, such as if a man was entitled to be called "Esquire," or if he was a merchant or a banker, but in practice the special jury list was largely made up on the basis of rateable qualification (i.e. liability for local property tax in England).
-- Wikipedia
Legal Definition
One selected in a particular way by the parties. A pannel is made out, and each party is entitled to strike from it the names of a certain number of jurors, as provided for by the local statutes, and from those who remain, the jury in that case must be selected. This is also called a struck jury.
-- Bouviers Law Dictionary
Legal Definition
A jury ordered by the court, on the motion of either party, in cases of unusual importance or intricacy. Called, from the manner in which it is constituted, a "struck jury." 3 Bl. Comm. 357. A jury composed of persons above the rank of ordinary freeholders; usually summoned to try questions of greater importance than those usually submitted to common juries. Brown.
-- Black's Law Dictionary
Legal Definition
A jury of men of a certain class or business.
-- Ballentine's Law Dictionary