Singlet

Singlet may refer to:
 * singlet state, in theoretical physics, a quantum state with zero spin
 * Singlet fission, in molecular photophysics
 * in spectroscopy, an entity appearing as a single peak; see NMR spectroscopy
 * in optics, a single lens element, the building blocks of lens systems; see lens (optics)
 * a one-piece collarless garment, also known as a sleeveless shirt or vest
 * wrestling singlet, a one-piece garment specific to wrestling
 * BID/60, a British encryption machine
 * Singlet oxygen, the common name used for an excited form of molecular oxygen