Here's the breakdown:
* Milan was a renowned center for fashion and textile production during the Middle Ages.
* "Milanese" (referring to people from Milan) was a common term for someone skilled in fashion and hat making.
* "Milliner" evolved from "Milanese" as a profession, specifically for those who made and sold hats.
So, the term "milliner" essentially means someone who makes and sells hats, a profession that thrived in Milan and spread throughout Europe.