How would you call someone who gives classes to students despite not having a degree in teaching nor it being their main occupation ?
For example, a lot of "teachers" I had in college were actually professionals in the field they were teaching, who would only do this for 2 or 4 hours a week in addition to their main job.
In France I have heard the term "Chargé d'enseignement", which litterally means "In charge of teaching".
Is there a similar word or expression in English ? Or would you just call them teachers ?