S: (n) diversion, deviation, digression, deflection, deflexion, divagation (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"
W: (v) digress [Related to: digression] (lose clarity or turn aside especially from the main subject of attention or course of argument in writing, thinking, or speaking) "She always digresses when telling a story"; "her mind wanders"; "Don't digress when you give a lecture"
W: (v) divagate [Related to: divagation] (lose clarity or turn aside especially from the main subject of attention or course of argument in writing, thinking, or speaking) "She always digresses when telling a story"; "her mind wanders"; "Don't digress when you give a lecture"