zuó
yesterday
乍 mainly gives the sound zuó; 日 carries the meaning, anchoring 昨 in the passage of days. Think of it as the day that has already passed.
昨天
zuó tiān
昨日
zuó rì
昨儿
zuó r
(coll.) yesterday
昨儿个
zuó r ge
昨夜
zuó yè
last night
昨晚
zuó wǎn
yesterday evening