I think the term means, and has always meant, learning by non-traditional methods; a university or art school.

Workshops, online education, YouTube, mentorships, apprenticeships, and the hard-scrabble of just doing it again and again are what most think of as "self-taught".

And I think another part of it is the perseverance, and total commitment that one makes to learning a craft by the bootstraps. No ivory tower teachers, no student union nonsense, no wasted hours of downtime (one design class at ASU gave the students two months to design a 4 page brochure... seriously?), and only the diversions allowed got in the way.

Of course there were people all along the way giving this bit or that bit... but in the end, the entrepreneurial spirit of the designer is what has taken them to wherever they are.

Oh, and did I mention no student loans, no debt, no failed relationships leaving one crying for days and days and... uh... skip that part.