filter

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A porous material through which a liquid or gas is passed in order to separate the fluid from suspended particulate matter.
• noun A device containing such a material, especially one used to extract impurities from air or water.
• noun Any of various electric, electronic, acoustic, or optical devices used to reject signals, vibrations, or radiations of certain frequencies while allowing others to pass.
• noun A colored glass or other transparent material used to select the wavelengths of light allowed to reach a photosensitive material.
• noun Computers A program or device that blocks e-mail or restricts website access when specific criteria are met.
• intransitive verb To pass (a liquid or gas) through a filter.
• intransitive verb To remove by passing through a filter.
• intransitive verb Computers To use a filter to block or restrict access to.
• intransitive verb To pass through or as if through a filter.
• intransitive verb To come or go gradually and in small groups.

from The Century Dictionary.

• Same as felter.
• To purify or defecate, as water or other liquid, by passing it through a filter or any cleansing medium; strain.
• Specifically In analytic chemistry, to separate (a solution) from the solid matter contained in it, either for the purpose of collecting and saving the solid matter, usually a precipitate, or of preparing the solution for further operations.
• To percolate; pass through or as through a filter.
• noun See philter.
• noun A device for arresting and separating any matter mechanically suspended in a liquid.
• noun Specifically In fish-culture, a long box in which screens, usually of flannel, are placed, through which the water is filtered before it passes into the hatching-troughs. Also called filtering-box, filtering-tank.

from the GNU version of the Collaborative International Dictionary of English.

• noun 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 a pond, the bottom of which is a filter composed of sand gravel.
• noun 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.
• transitive verb To purify or defecate, as water or other liquid, by causing it to pass through a filter.
• transitive verb a porous unsized paper, for filtering.
• noun Same as philter.
• intransitive verb To pass through a filter; to percolate.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A device which separates a suspended, dissolved, or particulate matter from a fluid, solution, or other substance; any device that separates one substance from another.
• noun Electronics or software that separates unwanted signals (for example noise) from wanted signals or that attenuates selected frequencies.
• noun Any item, mechanism, device or procedure that acts to separate or isolate.
• noun mathematics, order theory A non-empty upper set (of a partially ordered set) which is closed under binary infima (a.k.a. meets).
• verb transitive To sort, sift, or isolate.
• verb transitive To diffuse; to cause to be less concentrated or focused.
• verb intransitive To pass through a filter or to act as though passing through a filter.
• verb intransitive To move slowly or gradually; to come or go a few at a time.
• verb intransitive To ride a motorcycle between lanes on a road

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb run or flow slowly, as in drops or in an unsteady stream
• verb pass through
• verb remove by passing through a filter
• noun an electrical device that alters the frequency spectrum of signals passing through it
• noun device that removes something from whatever passes through it