Can someone explain to me the meaning of non-binary?

I know it's supposed to be someone that isn't feeling being a man or a woman. But what else he/she can be?

I do get transgenders, because it's still binary, man to woman and woman to man.

It's not a criticise opinion, I genuinely don't understand the concept of outside the binary system, please explain it to me.🙏

Can someone explain to me the meaning of non-binary?
Can someone explain to me the meaning of non-binary?
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