This is the 77th most frequent Persian word.
شدن
"Shodan" (شدن) means "to become" or "to happen."
Here, 'شدن' (shodan) is used in the passive voice construction, similar to 'was' or 'were' in English.
این کتاب خوانده شد.
This book was read.
Here, 'شدن' (shodan) is used to mean 'to become', indicating a change of state or status.
من پزشک شدم.
I became a doctor.
In this context, 'شدن' (shodan) is used to describe an intensification or increase in degree.