There is teaching-only/research-only and teaching-and-research. teaching-and-research is the standard, research-only the elite, and teaching-only is usually seen as "not real professors".
Then for each of those the levels are student, temp, junior, senior.
They all have different names for some reason instead of straightforward ones, because egos.
Some of the combinations don't exist, in particular for teaching-only.
In general due to limited junior/senior positions, there is a massive amount of people at temp level, sometimes indefinitely.
The article above mostly rants about how the majority of the teaching is done by the teaching-only staff (as you would expect), and how they should be given more consideration. The truth is that the worth of a professor is measured by his research, not his teaching.