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. |
See also: Biquadratic
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.