underwool
/ˈʌndərˌwʊl/
noun
- The soft, fine, dense layer of fur beneath the outer coat of some animals, such as sheep, goats, or dogs, providing insulation.
- Cashmere comes from the soft underwool of cashmere goats.
- During spring, the dog sheds its thick underwool to stay cool.
- The underwool of the sheep is used to make warm winter clothing.