A waistcoat is common to men’s formal attire. It is a sleeveless vest that is worn over a collared dress shirt, with a tie or bow tie and over it is a coat or blazer. It is part of a man’s formal three piece attire also known as a tuxedo or a tux for short.
A waistcoat has vertical front opening with buttons to secure it. The waistcoats match either the shirt, trousers or the tie, depending on how the man likes to wear it.
The cut at the bottom of a waistcoat could be either a V cut or a straight cut.