Linear Regression and proposed substitute words

In MA1421, the last chapter that he would learn is known as Linear Regression.

It really is telling. Linear Regression.

Defining "Regression":
1) a trend or shift towards a lower or less perfect state.
2) a progressive decline of a manifestation of disease.
3) a retrograde motion.
4) the linear relationship between 2 correlated variables.

Cosmic irony, isn't it? The title of the very last chapter has multiple meanings and all of them connote negativity.

"Linear Regression". Why not "Linear Progression" or even a more neutral substitute, say, "Linear Relation"?

Why "Regression" of all words?

He really should stop finding divine significance, especially when it doesn't exist. Yes, he ought to remind himself that.