A dense, woolly covering of hairs on the surface of a plant or animal. The tomentum on the leaves of the plant helps to reduce water loss.
A network of fine, soft, matted hairs or fibers, especially on the surface of certain plants or animals. The tomentum on the caterpillar's body provides it with camouflage against predators.
Archaic Medicine: A soft, fleecy padding of lint or fibers used as a surgical dressing. In eighteenth-century hospitals, wounds were often bound with tomentum soaked in wine.