any of various pale or dull-coloured moths of the family Lymantriidae (or Laparidae), the hairy caterpillars of which are pests of many trees
See also gipsy moth, browntail moth, goldtail moth
Word origin
C19: so named because of the tufts of hair on the caterpillars
tussock moth in American English
any of a family (Lymantriidae) of moths whose caterpillars are covered with longtufts of hair: many, as the gypsy moth, are destructive pests of certain trees