Русско-англо-русский юридический словарь

The law of agency in South Africa regulates the performance of a juristic act on behalf or in the name of one person ("the principal") by another ("the agent"), who is authorised by the principal to act, with the result that a legal tie (vinculum juris) arises between the principal and a third party, which creates, alters or discharges legal relations between the principal and a third party. (Wikipedia)

The phenomenon of juridical acts exists in most, if not all, legal systems of the world. The concept of a juridical act, however, has mainly become popular in the legal systems that belong to the civil law tradition. In common law countries, one rather speaks of the exercise of a legal power. A consequence of this difference between legal cultures is that the English term "juridical act" has not reached the level of general usage.

A juridical act is an act performed with the intention to bring about legal consequences, specifically one where the law connects legal consequences to the act for the reason that they were intended.

Alternative expressions for "juridical act" in English are "legal act" and "legal transaction." (Introduction to Law by Jaap Hage, Antonia Waltermann, Bram Akkermans)

“Juridical act” is a key term in the civilian lexicon that expresses the fundamental principle of autonomy of the will. The notion of juridical act is premised on the idea that a person’s legal position can change—that is, the person can acquire, modify, transfer, or extinguish rights—either by that person’s voluntary act (juridical act) or by operation of law (juridical fact). (A Louisiana Theory of Juridical Acts)

Article 18 An adult has full capacity for civil conduct, and may perform juridical acts independently. (English translaction of the Civil Code of the People's Republic of China)