singlet

Short definition from Wiktionary

Noun

1. 1
   A set of one, an item not part of a larger set: A multiplet having a single member, especially a single spectroscopic peak.
2. 2
   A set of one, an item not part of a larger set: A quantum state having zero spin.
3. 3
   A set of one, an item not part of a larger set: A person who does not have a form of multiplicity; a single self or personality occupying one human body.
4. 4
   A single piece of clothing: A sleeveless buttonless shirt with a low-cut neck.
5. 5
   A single piece of clothing: A one-piece, tight-fitting uniform, usually made of spandex or nylon, required in wrestling and powerlifting.