Main article is here on wikipedia
My personal additional comment: Well, actually I've never got this wide range explanation when I was in Fashion school. It was more like straight to the point and only short history in fashion.
However as for explaining what was exactly the definition itself or the detail in fashion design had never occurred to me that it was this long and wide. I love Wiki for becoming the source of any information I want, almost everything. So, for beginners or anyone who are interested in this field fell free to find out more before you're involved inside.