n. One who sifts, in any sense; especially, one employed in the operation of sifting loose matter.n. A sieve, particularly one differing in form and use from the common sieve, as for sorting matter of differing sizes, sifting ashes from partly burned coal, or the like.n. plural Specifically, in ornithology, the lamellirostral birds, as ducks and geese; sievebeaks.n. In milling and baking, a machine for sifting flour preparatory to blending it or using it in baking. It consists of a sieve inclosed in a casing and fitted with a cylindrical brush which, revolving above the sieve, breaks up all the lumps and presses the flour through the sieve.