digress
verb/di.vɐ.ˈɡaɾ/medium
di·va·gar
Definition
To speak or write at length in a wandering, unfocused way, straying from the main subject; to let one's mind wander.
The professor tended to digress into fascinating but unrelated anecdotes.
I often digress when I'm telling a story.
Common collocations
to digress from the subjectto let one's mind wanderto ramble on
Etymology
Do latim 'divagari' (vaguear, andar sem rumo).