[英][?ha?dr?][美]['ha?dr?]
n.水螅; 難於根除的禍患; 九頭蛇;
復數：hydrae hydras
例句:
1.
Despite the best efforts of brands and officials, catching counterfeits is like slaying ahydra.
雖然各大品牌和政府機構為打擊山寨使盡了渾身解數，但是消滅山寨就像要殺死壹條九頭蛇壹樣困難。
2.
If you're like me, the list of books you want to read is a hydra.
如果妳和我壹樣，那麽妳所讀書之書的清單就像壹個九頭蛇