Meaning of “yesterday” - Learner’s Dictionary

yesterday

noun [ U ], adverb us uk /ˈjestədeɪ/
Extra Examples
There are a lot more people here today than there were yesterday.The ship was last sighted off the French coast at 8 o'clock yesterday evening.There was an interesting piece on alternative medicine in the paper yesterday.The last hostages were finally freed yesterday.I saw Kate and Nigel yesterday - they came over for dinner.

A1 the day before today:

I went to see the doctor yesterday.
yesterday morning/afternoon

(Definition of “yesterday” from the Cambridge Learner’s Dictionary © Cambridge University Press)