Any of numerous small, flat-bodied, wingless biting or sucking insects of the orders Mallophaga or Anoplura, many of which are external parasites on various animals, including human beings.

• 虱，寄生虫无数小的，身体扁平，没翼的咬人吸血昆虫，其中许多是多种动物的外部寄生物