- 1[uncountable] the part of food that helps to keep a person healthy by keeping the bowels working and moving other food quickly through the body synonym roughage dietary fiber Dried fruits are especially high in fiber. a high-/low-fiber diet He has been advised to increase his fiber intake. bran fiber
- 2[countable, uncountable] a material such as cloth or rope that is made from a mass of natural or artificial threads nylon and other man-made fibers
- 3[countable] one of the many thin threads that form body tissue, such as muscle, and natural materials, such as wood and cotton cotton/wood/nerve/muscle fibers (literary) She loved him with every fiber of her being. see moral fiber, optical fiber
Check pronunciation: fiber