parenthetical

/ˈpæ.ɹən.θɛt.ɪkl̩/

Etymology

From Medieval Latin parentheticus (from Late Latin parenthesis or Ancient Greek παρένθετος (parénthetos), + -icus) + -al. By surface analysis, par- + en- + thetical.

parenthetical means using, containing, or within parenthesis. Lexicurio rates it Rare gem — a strength score of 76 out of 100.

adj

Using, containing, or within parenthesis.“You wrote "Bob (my best friend) works in finance", but I think you should rephrase that parenthetical part.”
Explaining or qualifying something.
Incidental.

noun

A word or phrase within parentheses.
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.