Why is it called a smoking jacket?

The classic smoking jacket is a mid thigh-length jacket made from velvet or silk, or both. It features a shawl collar, turn-up cuffs, and toggle or button fastenings–or may simply be closed with a tie belt. ... It became fashionable to be depicted in one's portrait wearing a silk robe de chambré, or dressing gown. read more

The classic smoking jacket is a mid thigh-length jacket made from velvet, silk, or both. It has a shawl collar and turn-up cuffs and toggle or button fastenings, or may simply be closed with a tie belt. read more

In Italian, French and German the dinner suit is called 'smoking' (after the smoking jacket, which of course is something else). In American English it's called Tuxedo (after a club). The trousers of a dinner suit should in fact have silk piping in material matching the one on the lapels. read more