BIPYRAMIDAL
Bi`py*ram"i*dal, a. Etym: [Pref. bi- + pyramidal.]
Defn: Consisting of two pyramids placed base to base; having a pyramid at each of the extremities of a prism, as in quartz crystals.
BIQUADRATE
Bi*quad"rate, n. Etym: [Pref. bi- + quadrate.] (Math.)
Defn: The fourth power, or the square of the square. Thus 4x4=16, the square of 4, and 16x16=256, the biquadrate of 4.
BIQUADRATIC Bi`quad*rat"ic, a. Etym: [Pref. bi- + quadratic: cf. F. biquadratique.] (Math.)
Defn: Of or pertaining to the biquadrate, or fourth power. Biquadratic equation (Alg.), 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 Bi`quad*rat"ic, n. (Math.) (a) A biquadrate. (b) A biquadratic equation.
BIQUINTILE
Bi*quin"tile, n. Etym: [Pref. bi- + quintile: cf. F. biquintile.]
(Astron.)
Defn: An aspect of the planets when they are distant from each other by twice the fifth part of a great circle — that is, twice 72 degrees.
BIRADIATE; BIRADIATED
Bi*ra"di*ate, Bi*ra"di*a`ted, a. Etym: [Pref. bi- + radiate.]