bolter, clarifier, cradle, cribble, cribriformity, cribrosity, filter, grate, grating, honeycomb, lixiviator, net, percolator, porosity, porousness, purifier, refiner, refinery, riddle, rocker, screen, sieve, sievelikeness, sifter, sorter, sponge, strainer, winnow, winnowing basket, winnowing fan, winnowing machine