- Brit. a man's undershirt, esp. a sleeveless one
- Austral., N.Z. a short-sleeved or sleeveless knit top, as a T-shirt or tank top
- an atom that is freed from combination by being raised to a higher energy level
Origin of singletfrom single, modeled on doublet
- A sleeveless, tight-fitting undershirt or athletic shirt.
- A tight-fitting, one-piece garment consisting of shorts and a sleeveless top with a collar that sometimes dips low on the chest, worn in wrestling.
- Physics A multiplet with a single member.