It comes from the work of French scholar Michel Foucault and essentially posits that one way the status quo maintains power is by making it appear "normal" for them to be in power. If it seems normal, no one is questioning, and it's just easier to stay in power that way.
For example, years ago apartheid was considered normal in South Africa. Finally some people began to protest that racial segregation was not indeed normal, and while the change didn't happen overnight, apartheid is no longer the normal way of being in that county.
It used to be normal for fathers to go to work every day and for mothers to stay home all day. Today, all kinds of alternatives to this are accepted as normal.
These days, getting a college degree is the normal way to join the solid ranks of the middle class. In fact, in many disciplines you absolutely cannot participate if you do not have this degree, but that isn't the only way to gain a boatload of knowledge about something. Another example: it's normal to get your driver's license at age 16. But, in Europe, you mostly have to be 18 to get a driver's license. It's normal for a lot of people to want to spend your college years in an inebriated state. Being normal is not necessarily a good thing.
It used to be normal to expect to work as a manager all your life with one or more companies; today the so-called gig way of work is becoming normal.
If you're not pleased with something in your life, see if you're accepting it as normal when you don't have to.
