This is the 399th most frequent Turkish word.
geçtiğimiz
"Geçtiğimiz" means "the past" or "the previous" in English.
In this sentence, "geçtiğimiz" is used as an adjective to describe the noun "hafta" (week), indicating the week that has recently passed.
Geçtiğimiz hafta şehir dışına çıkmıştık.
Last week, we had gone out of the city.
Here, "geçtiğimiz" describes "günlerde" (days), referring to a period of days that have recently ended.
Geçtiğimiz günlerde hava oldukça soğuktu.
In the past days, the weather was quite cold.
In this case, "geçtiğimiz" modifies "yıl" (year), signifying the year prior to the current one.