The definition of a filter is something that separates solids from liquids, or eliminates impurities, or allows only certain things to pass through.noun
- A Brita that you attach to your water faucet to remove impurities from your water is an example of a water filter.
- When you stop to think about the impact of your words before you say them, this is an example of a filter between your brain and your mouth.
To filter is defined as to remove impurities or unwanted material, to gradually leave a place or to gradually become known.verb
- When you run water through a cloth to remove dirt and other debris, this is an example of a time when you filter water.
- When you look through applications and weed out the ones you know your boss won't like, this is an example of a time when you filter.
- When people slowly exit a movie theater after a show ends, this is an example of a time when they filter out of the theatre.
- When news of the casualties after a plane crash starts to slowly become known, this is an example of a time when the news filters out.
- a device for separating solid particles, impurities, etc. from a liquid or gas by passing it through a porous substance
- any porous substance used or suitable for this, as sand, charcoal, felt, etc.
- a device or substance that passes electric currents of certain frequencies or frequency ranges while preventing the passage of others
- a device or substance that partially or completely absorbs certain light rays: a color filter for a camera lens
Origin: ME filtre < OFr < ML filtrum, feltrum, felt, fulled wool (used for straining liquors) < Gmc: see felt
- to pass (a liquid or gas) through a filter
- to remove or separate (solid particles, impurities, etc.) from a liquid or gas by means of a filter: often with out
- to act as a filter for
Origin: Fr filtrer < the n.
- to pass through or as if through a filter
- to move or pass slowly: the news filtered through town
Used by arrangement with John Wiley & Sons, Inc.
- 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.
- Computer Science A program or routine that blocks access to data that meet a particular criterion: a Web filter that screens out vulgar sites.
- To pass (a liquid or gas) through a filter.
- To remove by passing through a filter: filter out impurities.
- Computer Science To use a filter to block access to (a website or Web content).
- To pass through or as if through a filter: Light filtered through the blinds.
- To come or go gradually and in small groups: The audience filtered back into the hall.
Origin: Middle English filtre, from Old French, from Medieval Latin filtrum, of Germanic origin; see pel-5 in Indo-European roots.
- filˈter·er noun
- filˈter·less adjective
filter - Computer Definition
A device that allows some signals to pass through but absorbs, attenuates, blocks, rejects, or removes all other signals, depending on their frequency (electrical) or wavelength (optical). Active filters require electrical power to operate, while passive filters do not. A low-pass filter passes all frequencies below a certain value, but blocks all others. A high-pass filter passes all frequencies above a certain value, but blocks all others.A band-pass filter passes all frequencies in a designated band, but blocks all others. See also absorption, active, attenuation, electrical, frequency, optical, passive, signal, and wavelength.
Used by arrangement with John Wiley & Sons, Inc.
(1) To select data. Filters use patterns (masks) against which all data are compared and only matching data are "passed through," hence the concept of a filter. For example, e-mail clients and servers can look for messages with text patterns that are recognized as spam and delete them. An e-mail client can be set up to filter messages and store them in separate mailboxes as a way of organizing the mail, or it can be set to alert the user when a certain type of message arrives. See Bayesian filtering and spam filter.
(2) To change data. In this usage of the term, the concept of a filter (a pass-through device) is less obvious, but nevertheless widely used. For example, a sort routine changes the sequence of data. A conversion routine (import or export filter) changes one type of data, text or graphics format into another. See image filter and parse.
(3) See packet filter.
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filter - Cultural Definition
filter - Medical Definition
- A porous material through which a liquid or gas is passed in order to separate the fluid from suspended particulate matter.
- A device containing such a substance.
- Any of various electric, electronic, acoustic, or optical devices used to reject signals, vibrations, or radiations of certain frequencies while passing others.
- A translucent screen, used in both diagnostic and therapeutic radiology, that permits the passage of rays having desirable levels of energy.
- A device used in spectrophotometric analysis to isolate a segment of the spectrum.
- To pass a liquid or gas through a filter.
- To remove by passing through a filter.
- To pass through or as if through a filter.
filter - Science Definition
- A material that has very tiny holes and is used to separate out solid particles contained in a liquid or gas that is passed through it.
- A device that allows signals with certain properties, such as signals lying in a certain frequency range, to pass while blocking the passage of others. For example, filters on photographic lenses allow only certain frequencies of light to enter the camera, while polarizing filters allow only light polarized along a given plane to pass. Radio tuners are filters that allow frequencies of only a narrow range to pass into an amplification circuit.
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