[mass noun] Fine, soft hair, especially that which covers the body and limbs of a human fetus.
- ‘Their face and body are covered in soft hair called lanugo.’
- ‘Nails and hair become brittle; the skin dries, yellows, and becomes covered with soft hair called lanugo.’
- ‘Although dry pups in lanugo are probably able to maintain their body temperature in cold weather, it does not appear they can do so if wet.’
- ‘Five months after conception, human fetuses grow a thin coat of hair, called lanugo, all over their bodies.’
- ‘The first to develop is the lanugo, a layer of downy, slender hairs that begin growing in the third or fourth month of fetal life and are entirely shed either before or shortly after birth.’
Late 17th century: from Latin, down, from lana wool.