Also, par⋅en⋅thet⋅i⋅cal.
Origin: 1770–80; back formation from
parenthetical < Gk
parénthet(
os) interpolated (verbid of
parentithénai, equiv. to
par- par- +
en- en- 2 +
the-, var. s. of
tithénai to put +
-tos v. adj. suffix) +
-ic +
-al 1 
Related forms: par⋅en⋅thet⋅i⋅cal⋅i⋅ty, par⋅en⋅thet⋅i⋅cal⋅ness, noun
par⋅en⋅thet⋅i⋅cal⋅ly, adverb