White tie: Strictly for evening, white tie is the pinnacle of male attire. It is the realm of kings and diplomats and vitally important to get right. All the formal cues are there: black or midnight blue tailcoat and trousers with shirt, bow tie and waistcoat in white.
Black tie: Also for evenings, 007’s favourite look means a tuxedo (also called a dinner jacket) and bow tie in black or midnight blue with a contrast lapel (often satin) in the same shade. The shirt is white and pleated, the waist is covered with a waistcoat or cummerbund. Black tie in more detail
Morning suit: As the name suggests, this is formal for daytime: coat tails and striped pants in black or grey. Besides black shoes, accessories are grey: waistcoat, Ascot tie and, should the occasion call for it, top hat.
Lounge suit/Cocktail dress: Similar in philosophy, one is for day (lounge), the other for night (cocktail). Simply, it’s a conventional, non-formal suit. Play safe with dark, matching suit, white shirt and necktie.
Smart Casual: Worn day or night, this relaxed style is a more laidback code for relaxed weddings indoors or out. Start with a button-up shirt and trousers, add a jacket—which may or may not match the pants. Variation from traditional, dark tones is permitted. Tie is up to you.
Informal/Casual Collared shirt and trousers, jacket optional.