di ‧ gress /daɪˈɡres/ BrE AmE verb [intransitive]
[ Date: 1500-1600 ; Language: Latin ; Origin: digressus , past participle of digredi 'to step aside' ]
to talk or write about something that is not your main subject:
Do you mind if I digress for a moment?
—digression /daɪˈɡreʃ ə n/ noun [uncountable and countable] :
After several long digressions he finally reached the interesting part of the story.