echidnaはハリモグラ。発音は/ɪkídnə/なので、「エキドナ」もしくは「イキドナ」が近い。
steal someone's heartは、「（人）の心を奪う、（人）の愛情を勝ち取る、（人）のハートを盗む、（人）のハートをとりこにする」（英辞郎）という意味。
「ハリモグラ」もそうだけれども、日本語の動物の名前は聞いたことがなかったとしてもなんとなく想像が付く場合が多いが（針のあるモグラっぽい動物？という感じで）、英語はラテン語やギリシャ語などが語源になっている場合が多いため想像すらつかない場合が多い。
echidnaの語源を調べてみると…
Australian egg-laying hedgehog-like mammal, 1810, said to have been named by Cuvier, usually explained as from Greek ekhidna "snake, viper" (also used metaphorically of a treacherous wife or friend), from ekhis "snake," from PIE *angwhi- "snake, eel" (source also of Norwegian igle, Old High German egala, German Egel "leech," Latin anguis "serpent, snake").
But this sense is difficult to reconcile with this animal (unless it is a reference to the ant-eating tongue). The name perhaps belongs to Latin echinus, Greek ekhinos "sea-urchin," originally "hedgehog" (in Greek also "sharp points"), which Watkins explains as "snake-eater," from ekhis "snake." The 1810 Encyclopaedia Britannica gives as the animal's alternative name "porcupine ant-eater." Or, more likely, the name refers to Echidna as the name of a serpent-nymph in Greek mythology, "a beautiful woman in the upper part of her body; but instead of legs and feet, she had from the waist downward, the form of a serpent," in which case the animal was so named for its mixed characteristics (early naturalists doubted whether it was mammal or amphibian).
と長い説明が。一般的にはギリシャ語でヘビを意味するekhidnaから来たものと思われるが、「ウニ」を意味する（もともとはハリネズミを意味する）ラテン語のechinus、ギリシャ語のekhinosから来ているのではないか、もしくはギリシャ神話のエキドナEchidnaからではないかとのこと。
【関連】
ハリモグラ(Wikipedia)
エキドナ(Wikipedia)
| echidna を各種辞書で検索 | |
| 英和辞典 | Weblio |
| 英和辞典 | 英辞郎 on the WEB |
| 英英辞典 | Cambridge English Dictionary |
| 語源辞典 | Online Etymology Dictionary |
| 俗語辞典 | Urban Dictionary |
| シソーラス | Thesaurus.com |
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