dinner jacket

noun2

1. •
   (US) A jacket, often white, corresponding to a tuxedo jacket.

   • Constant was fully dressed in blue-green evening shorts and a dinner jacket of gold brocade. — 1959
2. •
   (UK) The formal suit, typically black, that includes this type of jacket.

   • [They] sat in a pen in the corner, smoking cigarettes and reading magazines; four or five girls in black silk dresses and the same number of slight effeminate young men in dinner-jackets. — 1932