digression

英 [daɪ'greʃ(ə)n] 美[daɪ'grɛʃən]

• n. 离题；脱轨

1. a message that departs from the main subject

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"

3. wandering from the main path of a journey