Not all mini hats are fascinators, but all fascinators are mini hats.
Fascinators: These whimsical headpieces are typically worn to the side and are fastened to the head with clip or headband. They’re mini hats with pizazz.
Mini hats: These hats are pint-sized versions of any style of hat like sombreros and top hats. Mini party hats are often used to accessorize costumes or festive looks, such as a mini cowboy hat or a tiny Santa hat with your best ugly Christmas sweater.