An opera cloak is an ankle- or floor-length loose-fitting cloak of dark, luxurious fabric such as velvet, brocade or satin, to be worn over an evening gown for a woman or a man's white tie tail coat or black tie dress suit, named after its typical designation for the opera.
[1] It may be described as a fitted cloak (sometimes with sleeves), generally not as tailored as a coat.
For white tie, men's opera cloaks are frequently worn with a walking stick and top hat or opera hat.
[2] Like cloaks and capes, the opera coat is usually lined in a coloured expensive fabric, such as silk, or a weave like satin, for a more opulent look.
An opera coat often has an elegant or dramatic collar, and may have padded sleeves.