Exercise piece

• Acrobat's wear
• Body suit
• Gym suit
• 1-Down wear
• Worn by ballet dancers and acrobats for practice or performance
• A tight-fitting garment that covers the body from the shoulders to the thighs (and may have long sleeves or legs reaching down to the ankles)
• One-piece suit
• Long suit?

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1961, from uni- "one" + ending from leotard .

Wikipedia Word definitions in Wikipedia
A unitard is a skintight, one-piece garment with long legs and sometimes long sleeves, usually stopping at the wrists and ankles. It differs from a leotard in that a leotard does not have long legs. The garment can be considered a combination of a leotard ...