magic word
noun [ C usually singular ] uk/ˌmædʒ.ɪk ˈwɜːd/ us/ˌmædʒ.ɪk ˈwɝːd/
魔咒，咒语
a word said by someone performing a trick to help it work successfully
I'll just say the magic word and the rabbit will disappear - Abracadabra! 我念一下咒语，兔子就会消失——阿布拉卡达布拉！
Idiom
what's the magic word?idiom 该怎么说来着？（让孩子要东西时说“请”字的用语）
said to a child who has not said "please" when asking for something
"Can I have another chocolate?" "What's the magic word?" "Please." “我能再吃块巧克力吗？”“该怎么说来着？”“请给我一块。”