Русско-англо-русский юридический словарь

A plaintiff (Π in legal shorthand), also known as a claimant or complainant, is the term used in some jurisdictions for the party who initiates a lawsuit (also known as an action) before a court. By doing so, the plaintiff seeks a legal remedy, and if successful, the court will issue judgment in favor of the plaintiff and make the appropriate court order (e.g., an order for damages). [...]

In Hong Kong, Canada and the United States, as well as in both Northern Ireland and the Republic of Ireland, the legal term "plaintiff" is still in use. American usage traditionally limits the application of terms such as "claimant" and "claim form" to extrajudicial process in insurance and administrative law. After exhausting remedies available through an insurer or government agency, an American claimant in need of further relief would turn to the courts, file a complaint (thus establishing a real court case under judicial supervision), and become a plaintiff. (Wikipedia)

Administrative law is the body of law that governs the activities of administrative agencies of government. Government agency action can include rulemaking, adjudication, or the enforcement of a specific regulatory agenda. Administrative law is considered a branch of public law. (Wikipedia)

The majority, in my respectful view, rests its holding on mistaken premises, for its reasoning conflicts with the express language of the Clean Air Act (CAA or Act), with sound rules of administrative law, and with principles that preserve the integrity of States in our federal system. (law.cornell.edu)

The ruling of a court is its order or judgment whether on a particular issue or the final verdict. In administrative law a ruling is an interpretation of a regulation. (A Glossary of Terms For First Year Students, George Mason University)