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.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.