Any of numerous flatworms of the class Trematoda, including both external and internal parasites of animal hosts, that have a thick outer cuticle and one or more suckers or hooks for attaching to host tissue.

• 吸虫任一种吸虫纲的扁平蠕虫，包括以动物为寄主的各种生长于内部和外部的寄生虫，其外部有一层很厚的角质层，长有一个或多个吸口或钩子。用于附寄主的组织