/ləˈn(y)o͞ogō/
Noun
1. Very fine, soft, and usually unpigmented, downy hair on the body of a fetus or newborn baby. It is the first hair to be produced by the fetal hair follicles, and it usually appears on the fetus at about 5 months of gestation. It is normally shed before birth, around 7 or 8 months of gestation but is often present at birth and disappears on its own within a few days or weeks. (wikipedia.org)
2. Soft down or fine hair, specifically that covering the human foetus or a tumorous area. (wiktionary.org)
3. The fine downy hair covering a human fetus; normally shed during the ninth month of gestation. (wordnetweb.princeton.edu)
4. The soft woolly hair which covers most parts of the mammal foetus, and in man is shed before or soon after birth. (biology-online.org)
Word origin: Latin lana, “wool.”