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.-to purify or defecate, as water or other liquid, by causing it to pass through a filter.-to pass through a filter; to percolate.-same as philter.