What is formal?
There are four categories of formal:
 
White Tie (or Full Dress)
Classic Black Tie
Morning Wear
Creative Black Tie

White Tie (or Full Dress)

White Tie is at the height of formality and has a strict dress code: black tail coat and trousers, white Marcella pique wing collar shirt, white Marcella pique vest, white Marcella pique bow, white jewellery (cuff links), white pocket hanky and white gloves.

 
What makes my outfit formal?