虚きょ根こんきょこんMeanings1nounimaginary rootmathematicsMathematics term for a root of an equation that is an imaginary number. Used in algebra and complex analysis.二に次じ方ほう程てい式しきが虚きょ根こんを持もつ場ば合あい、判はん別べつ式しきは負ふになる。When a quadratic equation has imaginary roots, the discriminant becomes negative.