understand why it was called a T-shirt.
From Undershirt to Everyday Fashion
T-shirts were not always worn as regular outer clothing. In the beginning, they were mostly used as undershirts. Workers, sailors, and soldiers wore them because they were light, comfortable, and easy to wash.
Over time, people began wearing T-shirts on their own. They became especially
popular because they were practical and affordable. A T-shirt could be worn while working, relaxing, exercising, or spending time outdoors.
By the middle of the 20th century, the T-shirt had become more than
