Biquadratic

Bi·quad·rat·ic

Biquadratic

a.
  1. Of or pertaining to the biquadrate, or fourth power. (Math.)

Phrases & Compounds
Biquadratic equation
an equation of the fourth degree, or an equation in some term of which the unknown quantity is raised to the fourth power.
Biquadratic root of a number
the square root of the square root of that number. Thus the square root of 81 is 9, and the square root of 9 is 3, which is the biquadratic root of 81. Hutton.

Biquadratic

n.
  1. A biquadrate. (Math.)