抽象代数中，复四元数（英语：Biquaternion）为一数值w + x i + y j + z k，其中w、x、y、z为复数，而{1, i, j, k}等元素的乘积方式同四元群。其与相对论中的劳仑兹群有关。
英语百科
Biquaternion 复四元数
In abstract algebra, the biquaternions are the numbers w + x i + y j + z k, where w, x, y, and z are complex numbers and the elements of {1, i, j, k} multiply as in the quaternion group. As there are three types of complex number, so there are three types of biquaternion: