下调
xià diào , xià tiáo · HSK 7
to lower
📉 下调 = down (下) + adjust/tune (调) = adjust downwards, lower prices
下 — horizontal line 一 + mark below
下 is an indicative character: a long horizontal line represents a reference level, and a shorter stroke placed beneath it points to the area below. The original meaning 'below, down' comes directly from this spatial diagram, and it later extended to verbs like 'descend' and 'lower'.
调 — speech radical 讠(言) + 周 zhōu (phonetic)
调 is a semantic-phonetic compound. The 讠(言) radical signals 'speech' or 'words,' while 周 supplies the sound. Originally meaning to harmonize or coordinate through words, it later extended to 'tune,' 'adjust,' and 'melody' (read diào), and 'mix evenly' or 'mediate' (read tiáo).