device that removes something from whatever passes through it(noun.artifact)
source: wordnet30
an electrical device that alters the frequency spectrum of signals passing through it(noun.artifact)
source: wordnet30
Any porous substance, as cloth, paper, sand, or charcoal, through which water or other liquid may passed to cleanse it from the solid or impure matter held in suspension; a chamber or device containing such substance; a strainer; also, a similar device for purifying air.(noun)