This is the 1722nd most frequent Dutch word.
treffen
"Treffen" means "to meet" or "to hit" in English, depending on context.
In this sentence, 'treffen' refers to arranging to meet someone or a planned meeting.
We treffen om drie uur bij het station.
We meet at three o'clock at the station.
Here, 'trof' (past tense of 'treffen') means to encounter someone by chance.
Tijdens mijn reis trof ik een oude vriend.
During my trip, I encountered an old friend.
In this case, 'treffen' conveys the sense of affecting or impacting individuals or groups.