First off, the word "precess" is defined by Mirriam Webster as "movement". It is not defined as error, or anything else. "Precession" is based on the word precess and is usually associated with conical movement around the axis of rotation seen in almost any gyroscope, an example of which is easily seen in a football flying through the air. It is also what causes a gyro to slowly hunt around the axis of rotation, drifting or hunting which makes heading indicators lose their proper setting. But the word also defined more broadly as "where a gyro responds to a torque in one direction with a motion in another direction" to quote the link I put in my post. It is the same thing- we call one type of precession good when it makes instruments respond to movement in an aircraft, while the other is troublesome because it produces instrument error. Here's wiki's view if you would rather hear it from them. It's both types of gyroscope movement, the one where the gyro wobbles (bad) and the one where the gyro shows an indication (good).