Definitions
from The American Heritage® Dictionary of the English Language, 4th Edition
 n. A divisor of a quantity that when squared gives the quantity. For example, the square roots of 25 are 5 and 5 because 5 × 5 = 25 and (5) × (5) = 25.
from Wiktionary, Creative Commons Attribution/ShareAlike License
 n. Of a number, another number which, when squared, yields the original number; sometimes constrained to be the positive number when two solutions exist.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
 n. a number that when multiplied by itself equals a given number
Etymologies
Sorry, no etymologies found.
Examples

He liked 97 because it was the largest twodigit prime number, and he loved 81 because it was absolutely the only number out of all the literally infinite possibilities whose square root was also the sum of its digits.

Tympanum says that, by extracting the square root of 3630, we get 60 yards with a remainder of 30/60, or half a yard, which we add so as to make the oblong 60 x 60½.

I dare say one should be prepared for anything in a land where an illiterate peasant girl can give you the square root of a sixfigure number at first glance, but when I reflect on the skill and speed of those copyists, and the analytical genius that penetrated that code … well, it can still rob me of breath.

After some thought, he was convinced that the oftenseen square root relationship applied here.
gangerh commented on the word square root
Ta muchly, John.
November 8, 2008
john commented on the word square root
Copy and paste this: √
To get a menu of special characters on a Mac, put the cursor where you want the character to appear, then select 'Edit > Special Characters...' in the Finder. A window will pop up, in which you can select the character you want and click 'insert', and it'll appear.
November 8, 2008
gangerh commented on the word square root
Can anyone tell me please how to put a square root sign in a word?
November 7, 2008