The "T" in "T-shirt" primarily refers to the shape of the garment itself. When laid flat, a T-shirt resembles the uppercase letter "T," with the vertical body of the shirt and the horizontal sleeves forming this shape
. Additionally, there is an association of the "T" with "training," as T-shirts were originally used by the military, particularly the U.S. Navy, as practical undershirts worn during physical training and warm climates
. In summary, the "T" in T-shirt stands for both the distinctive "T" shape of the shirt and its historical use as a training garment in the military. This dual meaning highlights the T-shirt's origins as a practical and comfortable piece of clothing that evolved into a staple of casual fashion
