This is the 13053rd most frequent Turkish word.
kapatırken
"Kapatırken" means "while closing" in English.
The word 'kapatırken' is used to indicate the simultaneous action or state occurring during the process of shutting down something.
Bilgisayarımı kapatırken dosyalarımı kontrol ediyorum.
While shutting down my computer, I check my files.
The word 'kapatırken' here implies that the speaker performed another action (wishing good evening) during the act of closing the shop.
Dükkanını kapatırken müşterilerine iyi akşamlar dedi.
While closing his shop, he wished his customers a good evening.
In this sentence, 'kapatırken' denotes an ongoing activity (turning off lights) during which another action was occurring (students watching the teacher).