正線 [－线]

Jyutping zing3 sin3
Pinyin zhèng xiàn

Definitions (粵典–words.hk)
  1. 名詞、術語
    粵曲​用語​，​即​係​西​樂​嘅​C​大調​；​同反線​相對
    C major in Cantonese Opera; literally: regular line