filter -
device that removes something from whatever passes through it
device any clever maneuver; "he would stoop to any device to win a point"; "it was a great sales gimmick"; "a cheap promotions gimmick for greedy businessmen"
filter A porous material for separating suspended particulate matter from liquids by passing the liquid through the pores in the filter and sieving out the solids.\n(Source: MGH)
filter Any item, mechanism, device or procedure that acts to separate or isolate.
filter To separate or isolate components from one another with the help of a filter.