The right of a citizen of the Russian Federation to appeal to state bodies and bodies of local self-government is one of the oldest human rights. It is an integral part of the mechanism for the implementation of a large number of subjective rights and freedoms. However, the concept of the legal category “citizen’s appeal” contained in the Federal Law “On the Procedure for Considering Appeals of Citizens of the Russian Federation” is not informative and creates many questions and problems. It is difficult to establish the content of the category “citizen’s appeal” because the word “appeal” is a verbal noun and has several meanings in Russian. In order to establish the true meaning of the term “citizen’s appeal”, the authors conducted a lexical analysis of the word “appeal” and examined its use in legal acts. Based on the analysis, it has been established that the term “appeal” in normative acts is used in different meanings and, to clarify it, an additional term is required that would explain the context of the use of the word “appeal”. Then, using specific legal methods of cognition (formal-legal, formal-logical, systemic, technical-legal methods), the authors analyzed the legislative definition of the term “citizen’s appeal”, namely, its understanding in the decisions of the Constitutional Court of the Russian Federation, the Supreme Court of the Russian Federation, and in special legal literature. The authors have formulated the definition of the category “citizen’s appeal”: it is the will of a person (group of people or organization) guaranteed by the Constitution of the Russian Federation, corresponding in its form to the normatively established rules and expressed in the form of a written, oral or implied-in-fact requirement to a state body or local government. The appeal is aimed at realizing the subjective rights, freedoms and legitimate interests of the applicant and third parties. The definition includes the necessary and sufficient set of essential characteristics that reveal the analyzed phenomenon, namely: constitutional conditionality, the proper applicant (subject of the appeal), the proper addressee, the form of expressed will, the purpose of the appeal. The absence of any of the above elements eliminates the citizen’s appeal as such or transforms it into a different kind of expression of will. Based on this theoretical construct, a new legislative definition of the legal category “citizen’s appeal” is formulated. The terms “applicant” (citizen, group of citizens, or organization sending the appeal) and “organization that performs publicly significant functions” (a legal entity established by a public law entity with the aim of performing non-commercial functions or a legal entity that exercises certain state or municipal powers) are also defined.