Meaning of “dwell on/upon sth” - Learner’s Dictionary

dwell on/upon sth

phrasal verb with dwell uk us /dwel/ verb (past tense and past participle dwelt, dwelled)

to keep thinking or talking about something, especially something bad or unpleasant:

I don't want to dwell on the past.

(Definition of “dwell on/upon sth” from the Cambridge Learner’s Dictionary © Cambridge University Press)