Lewis & Short

partĭcĭpĭālis, e, adj. [participium], in gram., of the nature of a participle, participial: verba, Quint. 1, 4, 29; cf. so of supines and gerunds, Prisc. p. 808; 822 P.
Adv.: partĭcĭpĭālĭter, in the manner of a participle, participially, Fest. s. v. ostentum, p. 194 Müll.; so id. ib. s. v. torrens, p. 352 Müll.