As was kind of mentioned, the term “self-made” is not meant to imply that someone created everything he has on his own, from scratch. Obviously no one could do that. As the “rational optimist” points out, not a single person on Earth knows how to make a simple computer mouse…or even a pencil.
When someone says “self-made” they are meaning that they built/earned their fortune through their own personal efforts, as opposed to simply receiving it from someone else…that is, they created wealth…as opposed to simply taking wealth that someone else created. This was covered really well (and in many different ways) in the Elizabeth Warren thread.