1. in former days, when the Omahas and Ponkas had no machinery, whatever they wished to cleanse from dust and litter, as corn, they would pour out from the top of a scaffold into a robe placed on the ground. The wind blew away the litter (mhic̸e ac̸ai) as the grain fell. 2. to sift, shake in a sieve; to sift or fan, as in a wheat-fan