Question

Rules or principles of justice or fairness to supplement the law are called

Answer 1

They are called "equity."

Answer 2

Equity had to improve the common law. The idea of equity derived in order to support fair results in some special situations. In the past, there were some severe judgments in English universal law. Essentially equity was there with the purpose of mitigating difficulties of general law. Equity is based on a constitutional evaluation of fairness as objected to the severe and rigid rule of general law. Authorities of a Court of Equity obtained from the Principle of Justice.