The ABSOLUTE VALUE of a number is its distance from zero on a number line.  It is ALWAYS expressed as a POSITIVE number.

|-4| = 4   and   |4| = 4   

Absolute value can be thought of as a measurement or distance.  The concept of a direction or a sign (i.e. positive or negative) is not relevant.

For instance, SPEED is a raw measurement of a rate (distance over time) without regard to direction.  VELOCITY indicates BOTH speed and direction.  A rocket launches UP into space with positive velocity and returns DOWN to earth with negative velocity.  Its speed in both cases would be referred to as simply a positive number.