In essence, things that are not formal legal rights, yet still fairly consistently impact how one is treated by others.
For example, men have social permission to be promiscuous largely without censure, and women do not. The standards of grooming and attention to attire expected of men are much lower than those expected of women. On the other hand (because these kinds of things don't go all one way), women have much more social permission to act masculine than men do to act feminine.
And this doesn't only mean things that *only* happen to women, but not men. It can also mean things that happen *a lot more* to women than to men.
For example, mechanics are much more likely to assume women know nothing about cars, and thus talk down to and/or actually scam them. It doesn't mean men never get talked down to or scammed, but it *does* mean that, in general, if you have ladyparts, your mechanic is much more likely to treat you like a gullible idiot.
Men are much more likely to interrupt women who are speaking than women are to interrupt men, and I think men are somewhat more likely to interrupt women than they are to interrupt other men. The "present your idea as my own" thing is something that men do to women a lot more than men or women do to men. And so on.