an idea, problem, situation etc that you discuss or write aboutCan we talk about a different subject please?
subject of: He’s never mentioned the subject of money.
The subject of our debate today will be the environment.
bring up a subject (=deliberately start talking about a subject): It was Carol who brought up the subject of sports facilities.
get onto a subject (=start talking about a subject without planning to): Somehow we got onto the subject of education.
drop a subject (=deliberately stop talking about a subject): Look, I don’t want to talk about it, so can we drop the subject?
get off the subject (=stop talking about something because you have become interested in something else): We’re getting off the subject here – let’s get back to your book.
change the subject (=deliberately start talking about something else to avoid an argument or embarrassing situation): Can we change the subject, please?