The right to peaceably assemble and to petition the government for redress of grievances; guaranteed by the First Amendment to the US Constitution WordNet 3.0 & Open English WordNet

Freedom of peaceful assembly, sometimes used interchangeably with the freedom of association, is the individual right or ability of people to come together and collectively express, promote, pursue, and defend their collective or shared ideas. Wikipedia

The individual right to come together and collectively express, promote, pursue and defend common interests Wikipedia Disambiguation

Right to form social or political groups and hold meetings Wikidata

The right of citizens to freely congregate or assemble anywhere should they wish to. Wiktionary

Right of citizens to freely congregate or assemble. Wiktionary (translation)