In the colloquial sense, a petition is a document addressed to some official and signed by numerous individuals. A petition may be oral rather than written, and in this era may be transmitted via the Internet. The term also has a specific meaning in the legal profession as a request, directed to a court or administrative tribunal, seeking some sort of relief such as a court order.
A petition can also be the title of a legal pleading that initiates a case to be heard before a court. The initial pleading in a civil lawsuit that seeks only money (damages) might be titled (in most U.S. courts) a complaint; an initial pleading in a lawsuit seeking non-monetary or "equitable" relief such as a request for a writ of mandamus or habeas corpus, or for custody of a child or for probate of a will, would instead be termed a petition.
Petitions were a common form of protest and request to the British House of Commons in the 18th and 19th centuries, the largest being the Great/People's Charter, or petition of the Chartists. They are still presented in small numbers.
The Petition Clause of the First Amendment to the U.S. Constitution guarantees the right of the people "to petition the Government for a redress of grievances." The right to petition has been held to include the right to file lawsuits against the government.
Other types of petitions have included those which sought to free Nelson Mandela during his imprisonment by the former apartheid government of South Africa. The petitions had no legal effect, but the signatures of millions of people on the petitions represented a moral force which may have helped to free Mandela and to end apartheid. Non-governmental organizations such as Amnesty International often use petitions in an attempt to exert moral authority in support of various causes.
In February 2007, an online petition against road pricing on the UK Prime Minister's own website attracted over 1.8 million e-signatures, from a population of 60 million people (although it has not been verified that there was only one e-signature per person, merely one per email address). The site was official, but experimental at the time. Shocked government ministers were unable to backtrack on the site's existence in the face of national news coverage of the phenomenon. The incident has demonstrated both the potential and pitfalls of online e-government petitions. It remains to be seen if policy will be permanently affected.