1 an idea, problem, situation, etc. that you discuss or write about
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?
Synonyms and related words