branch off phrasal verb ( see also ↑ branch )
1 . if a road, passage, railway etc branches off from another road etc, it separates from it and goes in a different direction SYN fork off
branch off from
a passage branching off from the main tunnel
2 . British English to leave a main road SYN fork off
branch off from/into
We branched off from the main road and turned down a country lane.
3 . to start talking about something different from what you were talking about before
branch off into
Then the conversation branched off into a discussion about movies.