This is the 901st most frequent Armenian word.
երէկ
"Erēk" (երէկ) means "yesterday" in English.
The word 'երէկ' is used as a time indicator to specify the day before today.
Երեկ ես գնացի գրադարան։
Yesterday, I went to the library.
The word 'երեկ' appears in its possessive form 'երեկուայ' (of yesterday) to indicate a thought process regarding the day before.
Ես կմտածեմ երեկուայ մասին վաղը։
I will think about yesterday tomorrow.
Here, 'երէկ' is again used to specify the timeframe as the day before.