What is the meaning of Singlet?

A set of one, an item not part of a larger set, particularly:

A multiplet having a single member, especially a single spectroscopic peak.

A quantum state having zero spin.

A person who does not have a form of multiplicity; a single self or personality occupying one human body.

A single piece of clothing, particularly:

  1. A sleeveless buttonless shirt with a low-cut neck.

    A sleeveless buttonless shirt with a low-cut neck.

    A one-piece, tight-fitting uniform, usually made of spandex or nylon, required in wrestling and powerlifting.

    a singlet, short, sleeveless type of shirt, worn alone (as in sports) or as undershirt; originally only for men

    vest, singlet

    Source: wiktionary.org