水母在英语中被称为 "jellyfish"。这个词来源于拉丁语 "medusa"，意为"蜇人的女妖"。在拉丁语中，"medusae" 是一个表示复数形式的词，因此 "medusa" 可以表示单个水母。

例句：

The beach was closed due to a large number of jellyfish that had washed up on shore. (海滩因为大量水母冲上岸而被关闭。)

Jellyfish have a simple nervous system that allows them to sense their surroundings and react to stimuli. (水母有一个简单的神经系统，使它们能够感知周围的环境并对刺激做出反应。)

The jellyfish's tentacles are covered in stinging cells that can be used to capture prey and defend against predators. (水母的触手上覆盖着可以用来捕捉猎物和抵御捕食者的刺激细胞。)