Tuxedo

The lapel gives it away. A tuxedo jacket carries silk or satin facing on the lapel, usually matched by a stripe down the outside seam of the trouser; a business suit wears the same cloth throughout and has neither. Everything else follows from that. A tuxedo takes a bow tie rather than a long tie, is worn with a dress shirt, and needs the waist covered by a cummerbund or a waistcoat. A suit is daywear that can be dressed up. A tuxedo is evening wear, and it cannot be dressed down.

To the reception, yes — it has become the standard thing for a groom to change into once the ceremony is over, and for guests at a cocktail evening. To the ceremony itself, no. The mandap belongs to a sherwani or a jodhpuri, because the wedding day is an Indian occasion in an Indian register, and a tuxedo will read as a man who came from somewhere else. Many grooms wear both across the same week.

Black is the default and the hardest thing to get wrong. Midnight navy is the quieter, cleverer choice: under artificial light it reads blacker than black, and the satin lapel separates from the body more cleanly, which photographs beautifully. Ivory belongs to a daytime or a summer function rather than an evening one. If the stage lighting is heavy, as it is at a sangeet, a deep jewel shade holds its detail where flat black disappears.