Must be the midwinter blues....

[Triathlete]

Billy, wtf is a singlet?

Bart

A thin, breathable shirt worn by runners usually made of some sort of tech material.
Definately not something you would want to wear if the temp was much below the 60's except mybe as a base layer.

[tom4bren]

Definately not something you would want to wear ... on a date.

[Chopper]

That thing they made you wear in high school wrestling was called a Singlet also, sort of a onesie