Many assume the lines are just decoration. Others think they’re there to help you fold the towel neatly. Some even believe they’re a brand style choice. The truth is actually much more practical — and kind of clever.Those lines are called dobby borders, and they serve several important purposes.

First, they help with absorption control. Towels are designed to soak up water, but if the entire towel were thick and fluffy, it would dry very slowly and wear out faster. The woven line creates a section that dries quicker, helping the towel stay fresh and reducing that musty smell people hate.

Second, the lines add strength and durability. Towels go through a lot — washing, drying, pulling, twisting. The dobby border reinforces the fabric, preventing fraying and stretching at the ends. Without it, towels would lose their shape much faster.
Another reason is shape retention. The lines help the towel keep its original size and structure after repeated washes. That’s why old towels without strong borders often look warped or uneven over time.