Definition of "parenthetical" in English

adjective

1. using, containing, or within parenthesis

   • the parenthetical portion of the sentence "Bob (my best friend) works in finance"

2. that explains or qualifies something

3. that is incidental

noun

1. A word or phrase within parentheses.

2. (screenwriting) A descriptor or modifier enclosed within parentheses and put, indented, in a line of dialogue to describe how it should be acted or directed onscreen.