This is the 5228th most frequent Russian word.
обменялись
"Exchanged"
In this sentence, 'обменялись' is used to describe a mutual action where each party exchanged items with the other, specifically books.
Мы обменялись книгами на прошлой неделе.
We exchanged books last week.
Here, 'обменялись' indicates the reciprocal act of speaking kind words to one another, emphasizing politeness.
Они обменялись любезными словами перед уходом.
They exchanged pleasantries before leaving.
In this context, 'обменялись' refers to the act of sharing personal contact details with each other.