In practical, non-nerdy terms, a higher Denier indicates a thicker, heavier, and more tear- and abrasion-resistant fabric. It’s not really as simple as that, though. The fiber itself makes a big difference. Cordura nylon, for example, is renowned as a tough, durable fabric. But it’s also expensive, so some clothing manufacturers opt for a cheaper, no-name polyester material to keep the price down.