Cotton duck -  (from Dutch doek,"linen canvas"), also simply duck, sometimes duck cloth or duck canvas, commonly called "canvas" outside the textile industry, is a heavy, plain woven cotton fabric. There is also linen duck, which is less often used.

Duck is used in a wide range of applications, from sneakers to over tents to sandbags.

Duck fabric is woven with 2 yarns together in the warp and a single yarn in the weft.

By far the most popular workwear fabric, cotton duck is a weighty, plain-but-strong woven canvas. Despite its name, this hardy workwear fabric has nothing to do with waterfowl or their feathers. The term "duck" comes from the Dutch word doek, which refers to a linen canvas once used for sailors’ white trousers and outerwear. The word "cotton" has been added to modern duck items simply to distinguish them from traditional linen duck. Interestingly enough, though, cotton duck is related to another type of work-ready duck. Duct tape, often called "duck tape," was originally manufactured by adding an adhesive backing to regular cotton duck.

You’ve heard the expression "tougher than nails." Well, cotton duck may be "tougher than sails." The same general type of canvas duck used for many work clothes has often been used for traditional boat sails, since the thick cotton weave is incredibly resistant to tearing and rough wear. This workwear fabric is also found in four-walled tents, shoes and sand bags. Usually offered in drab colors like unbleached white, tan, and shades of brown or green, cotton duck work clothes never look very dirty even when they are.

The advantages of cotton duck workwear fabric are many. For example:

• It has a relatively smooth surface that isn’t prone to snagging and tearing.
• It is probably second only to leather in the class of true workwear fabrics in its ability to block the wind (which can be more important than anything on a blustery winter jobsite).
• It is somewhat burn-resistant, albeit still certainly flammable. If you’re sleeping by a campfire or welding in the shop, a few small sparks or hot ashes won’t ruin the fabric, unlike nylon or other synthetics that end up with tiny pinholes everywhere in the same situation.
• It may feel stiff and uncomfortable at first, but after being washed and worn a few times should feel quite comfortable.