Definition of Extraordinary Remedies
The writs of mandamus, quo warranto, habeas corpus, and some others tire often classified or termed “extraordinary remedies,” in contradistinction to the ordinary remedy by action. Under Rules practice in most states, most extraordinary “writs” have been abolished. In any action seeking relief formerly obtainable under any such writ, the procedure shall follow that of a regular action.
That's the definition of Extraordinary Remedies in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.