Adding to other voices in this thread that the title does not explain academic ranks, it explains North-american academic ranks. There are a variety of academic systems worldwide and in numbers of academics, production, and diversity, USA forms a minority.

A better title would therefore be: “North-american Academic Ranks Explained or What on Earth Is an Adjunct?”

This is not nitpicking. This is about stating clearing the cultural context to not invisibilise discussions that are not centred on US culture.