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Jyutping sau2 zoeng2 sam1
Pinyin shǒu zhǎng xīn

Definitions (Wiktionary)
  1. noun, informal
    centre of the palm
  2. noun, figuratively
    realm of someone's control

手掌心 [---]

Jyutping
Pinyin shǒu zhǎng xīn

Definitions (CC-CEDICT)
  1. see 手心[shou3 xin1]
Examples (Tatoeba—Mandarin-English)
  1. Mandarin
    三天之后,也就是下周一,时机就成熟了,到时教授和其帮派的骨干分子都会落入警方的手掌心。
    三天之後,也就是下週一,時機就成熟了,到時教授和其幫派的骨幹分子都會落入警方的手掌心。
    sān tiān zhī hòu , yě jiù shì xià zhōu yī , shí jī jiù chéng shú le , dào shí jiào shòu hé qí bāng pài de gǔ gàn fēn zǐ dū huì luò rù jǐng fāng de shǒu zhǎng xīn 。
    • In three days—that is to say, on Monday next—matters will be ripe, and the Professor, with all the principal members of his gang, will be in the hands of the police.
Examples (粵典–words.hk)
  1. Cantonese
    你逃唔出我嘅手掌心!
    你逃唔出我嘅手掌心!
    nei5 tou4 m4 ceot1 ngo5 ge3 sau2 zoeng2 sam1!
    • You are under my control!