昨 Origin — Chinese Character Wiki

zuó HSK1

yesterday

Phonosemantic compound. 日 represents the meaning and 乍 represents the sound.

Components

日 Meaning component

rì sun

乍 Sound component

zhà, zuò suddenly

Change in sound

昨 and 乍 don't sound similar in modern Mandarin due to historical phonetic changes. They were more similar in Old Chinese.
昨 *[dz]ˤak
乍 *[dz]ˤrak-s

Regular Modern

▼ More ▲ Less

	Middle Chinese	Old Chinese	Gloss
Baxter-Sagart	dzak	[dz]ˤak	yesterday

《說文》：“昨，壘日也。从日，乍聲。”