-theticalcomb. form
Primary stress is attracted to the first syllable of this combining form and vowels may be reduced accordingly; see e.g.
parenthetical adj. and n.Origin: A borrowing from Greek, combined with an English element. Etymons: Greek -θετικός , -al suffix1.
Etymology: < ancient Greek -θετικός (see -thetic comb. form) + -al suffix1. Compare -thetic comb. form.Found in adaptations of words ultimately of Greek origin from the late 16th cent., e.g. antithetical adj., hypothetical adj. Analogous formations after nouns in -thesis are found from at least the 19th cent., e.g. mesothetical adj., cosmothetical adj.
This is a new entry (OED Third Edition, November 2010; most recently modified version published online September 2018).