DIGRESSION
digression, excursion
(noun) wandering from the main path of a journey
diversion, deviation, digression, deflection, deflexion, divagation
(noun) 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”
digression, aside, excursus, divagation, parenthesis
(noun) a message that departs from the main subject
Source: WordNet® 3.1
Etymology
Noun
digression (countable and uncountable, plural digressions)
An aside, an act of straying from the main subject in speech or writing.
(generally uncountable) The act of straying from the main subject in speech or writing, (rhetoric) particularly for rhetorical effect.
(obsolete) A deviancy, a sin or error, an act of straying from the path of righteousness or a general rule.
(now rare) A deviation, an act of straying from a path.
(astronomy, physics) An elongation, a deflection or deviation from a mean position or expected path.
Synonyms
• (rhetorical device): digressio, ecbole
Source: Wiktionary
Di*gres"sion, n. Etym: [L. digressio: cf. F. digression.]
1. The act of digressing or deviating, esp. from the main subject of
a discourse; hence, a part of a discourse deviating from its main
design or subject.
The digressions I can not excuse otherwise, than by the confidence
that no man will read them. Sir W. Temple.
2. A turning aside from the right path; transgression; offense. [R.]
Then my digression is so vile, so base, That it will live engraven in
my face. Shak.
3. (Anat.)
Definition: The elongation, or angular distance from the sun; -- said
chiefly of the inferior planets. [R.]
Source: Webster’s Unabridged Dictionary 1913 Edition