University professors will say that they “work in academia.” For them, the people who work outside academia “work in industry” (or maybe government). It’s absurd when you think about it. The word industry conjures up images of factories or mines, but apparently home-care nurses and hockey players work in industry.
There’s a similar thing that happens in other sectors. Government employees (including politicians) say they work in “the public sector” and everyone else works in “the private sector,” including people who work for non-governmental organizations, charities, and nonprofits. Military folks refer to everyone else as “civilians.”
I suspect this is a psychological phenomenon: a tendency to create an over-simplification of the world where everyone not in my group gets a label which masks their variety.
See also: Social Identity Theory