Why Are Undershirts Called T-shirts?

As it turns out, the answer is surprisingly simple.

The “T” Refers to the Shape

A T-shirt gets its name from its basic shape. When laid flat, the garment forms the outline of a capital letter “T” — with the body creating the vertical line and the sleeves extending outward like the top bar of the letter.

The name became widely used in the early 20th century as short-sleeved cotton undershirts grew increasingly popular.

Before that, similar garments were often considered underwear rather than outer clothing.

Originally Designed as Undershirts

T-shirts were first introduced primarily as lightweight undershirts worn beneath military uniforms and work clothing. Soldiers, laborers, and factory workers appreciated them because they were comfortable, breathable, and easy to wash.

During the late 1800s and early 1900s, one-piece undergarments called “union suits” were common. Over time, manufacturers separated the top and bottom portions, creating what would eventually become the modern T-shirt.

The U.S. Navy helped popularize the garment after issuing white short-sleeved shirts to sailors in the early 1900s.