This is the 504th most frequent German word.
darum
"Darum" means "therefore" or "that's why."
In this case, "darum" connects cause and effect, acting as "therefore".
Er sagte, dass er seine Arbeit verloren hat, darum fühle ich mit ihm.
He said that he lost his job, therefore I sympathize with him.
Here, "darum" refers to the topic or matter being discussed.
Darum geht es in seiner Geschichte: das Streben nach Glück.
That is the point of his story: the pursuit of happiness.
Here, "darum" is used as a conjunction to mean "therefore" or "that’s why".