1. The numerical value of a real number without regard to its sign. For example, the absolute value of −4 (written |-4|) is 4. Also called numerical value.
2. The modulus of a complex number, equal to the square root of the sum of the squares of the real and imaginary parts of the number.

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.