Русско-англо-русский юридический словарь

Equity is a particular body of law that was developed in the English Court of Chancery.[1] It is not a synonym for 'general fairness' or 'natural justice'. It exists in domestic law, both in civil law and in common law systems, and in international law.[1] The tradition of equity begins in antiquity with the writings of Aristotle (epieikeia) and with Roman law (aequitas).[1][2] Later, in civil law systems, equity was integrated in the legal rules, while in common law systems it became an independent body of law. (Wikipedia)

The law of equity has developed over centuries to provide equitable doctrines and equitable maxims. (LawNow)

Equity law is derived from old English common law, when courts used their discretion to apply justice in accordance with natural law. Equity law supersedes common law and statute law when there is a conflict between the two and neither can appropriately bring the correct verdict. (UpCounsel)