1. 枝蔓：Diffusion 扩散 | Digression 枝蔓 | Dilthey 狄尔泰

2. 离题,枝节话：regress 退回,后退,逆行; 回归 | digression 离题,枝节话 | perhaps 也许,可能,多半

3. 离角,极方位距,天文：座标读取头 digitizing head | 离角,极方位距,天文 digression | 两面角 dihedral angle

noun

1. wandering from the main path of a journey

Synonym: excursion

2. a turning aside (of your course or attention or concern)

e.g. a diversion from the main highway
a digression into irrelevant details
a deflection from his goal

Synonym: diversiondeviationdeflectiondeflexiondivagation

3. a message that departs from the main subject

Synonym: asideexcursusdivagationparenthesis