In most English-speaking jurisdictions, including Hong Kong, Nigeria, Australia (except in federal jurisdiction), Canada, the United States, Northern Ireland and the Republic of Ireland, the legal term "plaintiff" is used as a general term for the party taking action in a civil case.
The word plaintiff can be traced to the year 1278, and stems from the Anglo-French word pleintif meaning "complaining". It was identical to "plaintive" at first and receded into legal usage with the -iff spelling in the 15th century.1
A plaintiff identified by name in a class action is called a named plaintiff.
In most common-law jurisdictions, the term "claimant" used in England and Wales since 1999 (see below) is used only in specific, often non-judicial contexts. In particular, in American usage, terms such as "claimant" and "claim form" are limited 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.
In England and Wales, the term "claimant" replaced "plaintiff" after the Civil Procedure Rules came into force on 26 April 1999.2 The move, which brings England and Wales out of line with general usage in English-speaking jurisdictions, was reportedly based on an assessment that the word "claimant" is more acceptable as "plain English" than the word "plaintiff".3 In Scottish law a plaintiff is referred to as a "pursuer" and a defendant as a "defender".4
The similar term "complainant" denotes the complaining witness in a criminal proceeding.
In the Federal Court of Australia, most plaintiffs are called "applicants", but in admiralty and corporations law matters they are called "plaintiffs".5
Case names are usually given with the plaintiff first, as in Plaintiff v. Defendant (orally, Plaintiff and Defendant). The party against whom the complaint is made is the defendant; or, in the case of a petition, a respondent. Subsequent references to a case may use only one of the names, typically that of the first nongovernmental party.6
Criminal cases are usually brought by the prosecution, not a plaintiff. The prosecution may bring the case formally in the name of the monarch, state or government. In many Commonwealth realms, this is the king (or queen, when the monarch is female), named the Crown, abbreviated R, thus R v Defendant (orally, R against (versus) Defendant). In several U.S. states, including California, Illinois, Michigan, and New York, the prosecution of a criminal case is captioned as The People of the State of, followed by the name of the state, or People for short.7
"Etymology Online". etymonline.com. Retrieved 2008-04-24. http://www.etymonline.com/index.php?term=plaintiff ↩
"Civil Procedure Rules". Ministry of Justice (UK). https://www.justice.gov.uk/courts/procedure-rules/civil/rules ↩
BBC, "UK Civil courts to modernize", 24 April 1999 http://news.bbc.co.uk/1/hi/uk/326414.stm ↩
"Glossary". Judiciary of Scotland. Archived from the original on 19 August 2019. Retrieved 24 January 2017. http://www.scotland-judiciary.org.uk/29/0/Glossary ↩
Federal Court of Australia – Starting a Matter https://www.fedcourt.gov.au/going-to-court/i-am-a-party/court-processes/starting-a-matter ↩
New York Official Reports Style Manual. Albany, New York: New York State Law Reporting Bureau. 2012. Retrieved April 7, 2023. https://www.nycourts.gov/reporter/new_styman.htm#1.3%20%28b%29 ↩
Simonson, Jocelyn (2019). "The Place of 'The People' in Criminal Procedure". Columbia Law Review. 119 (1). https://columbialawreview.org/content/the-place-of-the-people-in-criminal-procedure/ ↩