hydra
noun [ C ] uk/ˈhaɪ.drə/ us/ˈhaɪ.drə/
（古希腊神话中头被斩去后会复生的）多头蛇
in ancient Greek stories, a creature with many heads that grew again when cut off
难以根除的棘手问题
a difficult problem that keeps returning
英汉双解词典收录81607条英汉双解翻译词条，基本涵盖了全部常用单词的读音、翻译及用法，是英语学习的有利工具。