lanugo
la.nu.go \l*-'n(y)u:-(.)go-\ n [L, down - more at WOOL] : a dense cottony or downy growth; specif : the soft woolly hair t hat covers the human fetus and that of some other mammals
Webster's English Dictionaryla.nu.go \l*-'n(y)u:-(.)go-\ n [L, down - more at WOOL] : a dense cottony or downy growth; specif : the soft woolly hair t hat covers the human fetus and that of some other mammals