Webster's Revised Unabridged Dictionary · 1913

Biquadratic

Biquadratic ({not transcribed}) , adjective

[Prefix bi- + quadratic: compare French biquadratique.]

(Mathematics) Of or pertaining to the biquadrate, or fourth power.
Collocations (2)
Biquadratic equation (Algebra) , 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 , noun

(a)
(Mathematics) A biquadrate.
(b)
(Mathematics) A biquadratic equation.