Filter (?), n. [F. filtre, the same word as feutre felt, LL. filtrum, feltrum, felt, fulled wool, this being used for straining liquors. See Feuter.] 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.[1913 Webster]
Filter bed, a pond, the bottom of which is a filter composed of sand gravel. -- Filter gallery, an underground gallery or tunnel, alongside of a stream, to collect the water that filters through the intervening sand and gravel; -- called also infiltration gallery.[1913 Webster]
Filter, v. t. [imp. & p. p. Filtered (?); p. pr. & vb. n. Filtering] [Cf. F. filter. See Filter, n., and cf. Filtrate.] To purify or defecate, as water or other liquid, by causing it to pass through a filter.[1913 Webster]
Filtering paper, or Filter paper, a porous unsized paper, for filtering.[1913 Webster]
Filter, v. i. To pass through a filter; to percolate.[1913 Webster]
Filter, n. Same as Philter.[1913 Webster]