My daughter asked me a question that sounded incredibly simple: “What does the T in T-shirt stand for?” I was ready to answer immediately, but then I realized I had absolutely no idea. It was one of those everyday words I’d heard and used thousands of times without ever stopping to think about where it came from.

The answer is surprisingly straightforward. The “T” doesn’t stand for another word or some forgotten clothing term. Instead, it refers to the shape of the shirt itself. When a traditional short-sleeved T-shirt is laid flat with its sleeves extending outward, its body and sleeves roughly form the shape of a capital letter T.

The garment developed from underwear and undershirts worn around the beginning of the 20th century. Its simple construction, lightweight material, and lack of buttons made it practical, particularly as an undergarment and work shirt. Eventually, people began wearing these shirts by themselves rather than keeping them hidden beneath other clothing.

As the style became increasingly common, “T-shirt” became the natural description because of that recognizable T-shaped outline. What began as an extremely basic piece of clothing eventually became one of the most universal garments in the world, appearing in countless colors, designs, materials, and styles.

So when my daughter asked again, I finally had the answer: the T is simply describing what the shirt looks like when it’s spread out flat. After hearing it, the explanation seemed so obvious that I couldn’t believe I’d gone all these years without ever thinking about it.