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a. A porous material through which a liquid or gas is passed in order to separate the fluid from suspended particulate matter.
b. A device containing such a material, especially one used to extract impurities from air or water.
a. Any of various electric, electronic, acoustic, or optical devices used to reject signals, vibrations, or radiations of certain frequencies while allowing others to pass.
b. A colored glass or other transparent material used to select the wavelengths of light allowed to reach a photosensitive material.
3. Computers A program or device that blocks email or restricts website access when specific criteria are met.
4. Informal The ability or tendency to censor oneself, as to avoid causing embarrassment or offense: My roommate has no filter and says whatever he's thinking at the moment.
v. fil·tered, fil·ter·ing, fil·ters
1. To pass (a liquid or gas) through a filter.
2. To remove by passing through a filter: filter out impurities.
3. Computers To use a filter to block or restrict access to: a program that filters spam.
4. Informal To censor (oneself), as to avoid causing embarrassment or offense.
1. To pass through or as if through a filter: Light filtered through the blinds.
2. To come or go gradually and in small groups: The audience filtered back into the hall.

[Middle English filtre, from Old French, from Medieval Latin filtrum, of Germanic origin; see pel- in Indo-European roots.]

fil′ter·er n.
fil′ter·less adj.


The process of interpreting reported information on movements of aircraft, ships, and submarines in order to determine their probable true tracks and, where applicable, heights or depths.


n. filtración, el acto de filtrar a través de un filtro que impide el paso de ciertas moléculas;
___ operationoperación de ___.
References in classic literature ?
Daylight was filtering into the well from the orifice far above his head.
Now the cottage stood by the edge of a great green forest where the wind was always singing in the branches and the sunshine filtering through the leaves.
Through half open lids she saw the sunlight filtering through the leafy canopy above her--she wondered at the realism of her dream; full consciousness returned and with it the conviction that she was in truth being held close by strong arms against a bosom that throbbed to the beating of a real heart.
When next I awoke, a sickly yellow light was filtering in on me.
The dirtier they get, the more efficient they become at filtering the air.
A three-judge federal panel overturned CIPA in 2002, ruling that constitutionally protected speech would be blocked by the Web filtering.
Simply filtering on phrases such as "Get Rich Quick
Believing that the job of protecting students from Internet dangers has been done by installing filtering software at school is a prescription for more incidents such as this.
The system uses three cleaning stages to remove solids on and below the filter surface, preventing excess build-up that would otherwise reduce the system's flow rate and filtering effectiveness (Fig.
The effectiveness of an air cleaner depends on how well it collects pollutants from indoor air (a percentage efficiency rate) and how much air it draws through the cleaning or filtering element (measured in cubic feet per minute).
Just as computers can automate many mundane tasks, they can also automate e-mail organization: The first step in making e-mail work is learning to use an e-mail program's filtering options.
The pumps themselves still eventually need replacing, but now need to be replaced less often due to filtering.