parenthetical

Etymology
From (from  or, + ).

Adjective

 * 1) using, containing, or within parenthesis
 * the parenthetical portion of the sentence "Bob (my best friend) works in finance"
 * 1) that explains or qualifies something
 * 2) that is incidental

Noun

 * 1) A word or phrase within parentheses.
 * 2)  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.