Collins COBUILD Advanced Learner's English Dictionary - parenthetical

A parenthetical remark or section is put into something written or spoken but is not essential to it. Fox was making a long parenthetical remark about his travels on the border of the country. ADJ: usu ADJ n • parenthetically Well, parenthetically, I was trying to quit smoking at the time... And what, we may ask parenthetically, does it mean? ADV: ADV with cl, ADV with v, ADV adj