This is the 7872nd most frequent Japanese word.
回想
"回想" means "recollection" or "reflection on the past."
In this sentence, '回想' is used as a verb meaning 'to recollect' or 'to reminisce,' describing the act of looking back at past memories.
彼は過去の出来事を回想していました。
He was recollecting past events.
Here, '回想' denotes a noun referring to 'recollections' or 'reflections,' indicating the memories of the protagonist as portrayed in the movie.
その映画は主人公の回想を描いている。
That movie depicts the protagonist's recollections.
In this example, '回想する' is used as a verbal phrase ('to reminisce'), suggesting the value of reflecting on past experiences to uncover important realizations.