I was recently in a meeting with other university professors and one of them introduced himself as a "pseudo professor". The other, when introducing themselves reiterated that they understand what it means to be a pseudo professor as they have to raise more than 60% of their salary (or loosely pay themselves?). My question then is, who is a pseudo and a 'real' professor? This is in reference to the US higher education system.
This is unlikely to be a formal term anywhere, but a person who does what professors normally do (research, teaching, ...) but without a formal position/job/salary, might well describe themself as a pseudo professor.
Without a formal relationship to a university, they are probably less bound by university regulations, except, perhaps in treatment of students, if any.
Charles Darwin, for example, might be described as a pseudo professor. He had the skills and did the research but wasn't formally related to a university (if I remember correctly).
Industry researchers probably wouldn't so self-describe unless they had some sort of volunteer relationship with a university. "Think of me like a professor, but I'm really not."