digression in WordNet English dictionary

1. a message that departs from the main subject
   digression  aside  excursus  divagation  parenthesis 
   
2. a turning aside (of your course or attention or concern)
   "a diversion from the main highway"; "a digression into irrelevant details"; "a deflection from his goal"
   diversion  deviation  digression  deflection  deflexion  divagation 
   
3. wandering from the main path of a journey
   digression  excursion