1. A close-fitting one-piece garment worn by acrobats and dancers; a similar fashion garment
This word dates to the late 1800's in reference to Jules Léotard, a French trapeze artist who performed in the garment. Léotard died in 1870, but this word didn't emerge as the name of the garment he made famous until years after his death. He called the skin-tight one-piece a maillot, a general French word for tight-fitting shirts.
|Lady Gaga rocks the leotard look (source)|