dress suit

a man's suit for formal evening dress, with tail coat and open-front waistcoat.

Origin of dress suit

First recorded in 1800–10

Then I went East and entered a great college; went in for athletics, and wore my first dress-suit.

The Princess Elopes |Harold MacGrath
The sergeant is one of the detective bureau's "dress-suit men."

The Deluge |David Graham Phillips
Even Lord Vignoles (a sartorial connoisseur) had to concede that his dress-suit was a success.

The Sins of Sverac Bablon |Sax Rohmer
He would make it a dress-suit affair and give the little girl a chance.

Sister Carrie |Theodore Dreiser

Fred went below and got the bottle of medicine from his dress-suit case.

The Rover Boys on Treasure Isle |Edward Stratemeyer (AKA Arthur M. Winfield)

dress suit

an ensemble of matching formal evening wear