Source : Webster's Revised Unabridged Dictionary (1913)

Parenthetic \Par`en*thet"ic\, Parenthetical \Par`en*thet"ic*al\,
   a. [Cf. Gr. ?.]
   1. Of the nature of a parenthesis; pertaining to, or
      expressed in, or as in, a parenthesis; as, a parenthetical
      clause; a parenthetic remark.

            A parenthetical observation of Moses himself.
                                                  --Hales.

   2. Using or containing parentheses.

Source : WordNet®

parenthetical
     adj 1: as if using parentheses; "a parenthetical style" [syn: {parenthetic}]
     2: qualifying or explaining; placed or as if placed in
        parentheses; "parenthetical remarks" [syn: {parenthetic}]

parenthetical
     n : an expression in parentheses; "his writing was full of
         parentheticals" [syn: {parenthetical expression}]