Definition of Forms of action
Forms of action governed common law pleading and were the procedural devices used to give expression to the theories of liability recognized by the common law. Failure to analyze the cause of action properly, to select the proper theory of liability and to choose the appropriate procedural mechanism or forms of action could easily result in being thrown out of court. A plaintiff had to elect his remedy in advance and could not subsequently amend his pleadings to conform to his proof or to the court’s choice of another theory of liability. According to the relief sought, actions have been divided into three categories: real actions were brought for the recovery of real property; mixed actions were brought to recover real property and damages for injury to it; personal actions were brought to recover debts or personal property, or for injuries to personal, property, or contractual rights. The common law actions are usually considered to be eleven in number: trespass, trespass on the case, trover, ejectment, detinue, replevin, debt, covenant, account, special assumpsit, and general assumpsit.
Under the Rules of Civil Procedure (applicable in the federal and most state courts) there is now only one form of action known as a "civil action”. Fed.R.Civil P., Rule 2.
That's the definition of Forms of action in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.