[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.
Mr Lackersteen was even wearing a dinner-jacket—white, because of the season—and was completely sober. The boiled shirt and piqué waistcoat seemed to hold him upright and stiffen his moral fibre like a breastplate.
1971, E. M. Forster, chapter 37, in Maurice, Penguin, published 1972, page 162:
It was a dinner-jacket evening—not tails, because they would only be three—and though he had respected such niceties for years he found them suddenly ridiculous.