Carhartt is famous for using cotton duck fabric.
Cotton duck—also called duck cloth or duck canvas—is a heavy, tightly woven, plain-weave cotton fabric. Its dense construction gives it the toughness and abrasion resistance needed for workwear, making it a natural match for Carhartt’s original focus on railroad workers, farmers, builders, and other manual laborers.
“Duck” is not a reference to the bird. The name comes from the Dutch word doek, meaning “cloth,” and the material is a specific kind of canvas. Canvas is the broader category, while duck canvas is generally more tightly woven. Denim is also durable, but it is typically a cotton twill rather than a plain weave.
Carhartt has used both duck and denim since its early years, and the company now produces garments in many other materials and finishes. Nevertheless, cotton duck remains especially associated with its classic brown workwear, including jackets, pants, bibs, and coats designed for hard use.