singlet (noun) /ˈsɪŋɡlɪt/
1
A singlet is a term used in physics to describe a multiplet with a single member, a quantum state with zero spin, or a person without multiple personalities.
2
A single piece of clothing that can refer to a sleeveless buttonless shirt with a low-cut neck or a one-piece, tight-fitting uniform required in wrestling and powerlifting.