digression

名词 digression:

1. a message that departs from the main subject
   同义词：aside, excursus, divagation, parenthesis
2. a turning aside (of your course or attention or concern)
   同义词：diversion, deviation, deflection, deflexion, divagation
3. wandering from the main path of a journey
   同义词：excursion

1. A comment departing from the theme of discourse; a digression.
   插话，插曲，穿插与讨论的主题无关的看法; 离题话，
2. The direct address of an absent or imaginary person or of a personified abstraction, especially as a digression in the course of a speech or composition.
   呼语直接称呼不在场或虚构的人物或称呼拟人的事物，尤指作为演讲或作文过程中的离题话

di.gres.sion

n.（名词）
The act of digressing.
离题：离题的行为
An instance of digressing, especially a written or spoken passage that has no bearing on the main subject.
离题段落：离题的例子，特别是指写作或演说中与主题无关的段落

【引伸】
digres.sional
adj.（形容词）