1. overflowing, piling up, abundance MN.iii.230 (opp. apasādana).
2. (probably confused with ussāraṇa) tumult, uproar, confusion AN.iii.91, AN.iii.92 (variant reading ussāraṇa) = Pp.66 (= hatthiassarathâdīnaṃ c’eva balakāyassa ca uccāsadda-mahāsaddo Pp-a.249).

to ussādeti, cp. ussādita