What is the fourth power, or the square of the square. Thus 4x4=16, the square of 4, and 16x16=256, the biquadrate of 4 called?

biquadrate — The fourth power, or the square of the square. Thus 4x4=16, the square of 4, and 16x16=256, the biquadrate of 4. (Webster's 1913.)