Adverb
In a parenthetical manner; by way of parenthesis; by parentheses.
Source: Webster's dictionaryhe added parenthetically that he would not attend the wedding ceremony Source: Internet
This letter consists of two strands: an expositional or doctrinal strand, and a hortatory or strongly urging also translated "exhorting" strand which punctuates the exposition parenthetically at key points as warnings to the readers. Source: Internet
He parenthetically mentions those of Elizabeth's court, and names Oxford as "the most excellent" among them. Source: Internet
The system was a simple one in which each ship received a number which was appended to its ship type, fully spelled out, and added parenthetically after the ship's name when deemed necessary to avoid confusion between ships. Source: Internet