one-piece

[ wuhn-pees ]

/ ˈwʌnˌpis /

complete in one piece, as a garment: a one-piece snowsuit.

Also called one-piec·er. a one-piece garment.

Origin of one-piece

First recorded in 1875–80

Clearly the attraction was the nine-year-old girl in her one-piece.

A Nation of Onlookers: India’s Violence Against Women and America’s Guns |Dilip D’Souza |December 22, 2012 |DAILY BEAST
The one-piece dinner is as convenient and comfortable as the one-piece frock.

Dishes & Beverages of the Old South |Martha McCulloch Williams
In a fever of joyous haste she threw off her clothes and donned the dainty, one-piece bathing suit.

The Foolish Virgin |Thomas Dixon
The "one-piece" house was an assured thing from that time on.

The Boy's Book of New Inventions |Harry E. Maule

With the crankcase, they did not go all the way to the modern two-piece form but instead retained the one-piece construction.

The Wright Brothers' Engines and Their Design |Leonard S. Hobbs.
"I'm going to pretend to have a sick headache," said the other person, and I knew it was the one-piece lady.

Bab: A Sub-Deb |Mary Roberts Rinehart

one-piece

(of a garment, esp a bathing costume) made in one piece

a garment, esp a bathing costume, made in one piece