In philology, compounded of a number and variety of elements beyond the usual norm; exhibiting excessive intricacy of synthetic structure, as by the incorporation of objective and adverbial elements in the verb forms; incapsulated: as, a, polysynthetic word; characterized by such compounds: as, a polysynthetic language: first applied by Du Ponceau to the class of languages spoken by the Indian tribes of America. Also incorporative and (rarely) megasynthetic.In mineralogy, compounded of a number of thin lamellæ) in twinning position to each other, or characterized by this kind of structure: as, a polysynthetic twin. See twin.