quadratic surd

quadratic surd (plural quadratic surds)

1. (mathematics) An irrational number that is the solution of a quadratic equation of the form ${\displaystyle ax^{2}+bx+c=0}$, where ${\displaystyle a}$, ${\displaystyle b}$, and ${\displaystyle c}$ are integers and ${\displaystyle a}$ ≠ ${\displaystyle 0}$.