This is the 5186th most frequent Turkish word.
inen
"Descending" or "landing."
In this sentence, 'inen' is used to denote the action of descending or alighting, specifically referring to people departing from the bus.
Otobüsten inen insanlar hızlıca dağıldı.
The people getting off the bus quickly dispersed.
Here, 'inen' describes something that is falling or descending, in this case, rain.
Sabah kalktığımda inen yağmur tarlayı sulamıştı.
When I woke up in the morning, the descending rain had watered the field.
In this example, 'inen' conveys the motion of something moving downwards or landing, particularly the plane in this context.