noun
discriminant
In algebra, the expression b²−4ac used to determine the nature of the roots of a quadratic equation.
二次方程式の判別式が正ならば、二つの実数解を持つ。
If the discriminant of a quadratic equation is positive, it has two real solutions.
Compound of 判別 (discrimination, distinction) and 式 (formula, expression). The term is a direct calque from English 'discriminant'.