Many people often mix up the meaning of these three things when they don’t actually mean the same thing. The differences are simple.
A Suit is a set of jacket and trouser made from the same cloth which are generally worn on very formal occasions. They are traditionally worn on a collared shirt and a neck tie. The variations in cut, design, and cloth of a suit determine its social and work aptness
A Blazer can be called a less formal suit. The jacket and trouser are mostly of different fabric or different colour. It could be worn on a round neck or a polo T-shirt with a Jean trouser. Jackets are less formal when compared to suits.
A tuxedo is also called dinner suit. The jacket and the trouser could be of the same colour. The colour and type of lapel give tuxedo its distinguishing feature. It fits best for award ceremonies and dinners.