parenthesis vs divagation

parenthesis and divagation both are nouns.

Word	Noun	Adjective	Verb	Adverb
parenthesis	Yes	No	No	No
divagation	Yes	No	No	No

As nouns, parenthesis and divagation are synonyms defined as:

parenthesis and divagation: a message that departs from the main subject

Other synonyms of parenthesis include aside, digression, excursus.

parenthesis (noun)	divagation (noun)
either of two punctuation marks (or) used to enclose textual material	a turning aside (of your course or attention or concern)
a message that departs from the main subject	a message that departs from the main subject