Hot water being poured through coffee in a filter.
- The definition of a filter is something that separates solids from liquids, or eliminates impurities, or allows only certain things to pass through.
- 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.
- 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.
- Comput. software variously designed to examine data, e-mail messages, etc. and to process, delete, block, etc. those satisfying certain criteria: a spam filter that deletes spam sent to one's PC
- 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 of filterMiddle English filtre ; from Old French ; from Medieval Latin filtrum, feltrum, felt, fulled wool (used for straining liquors) ; from Gmc: see felt
- to pass through or as if through a filter
- to remove or separate by means of a filter: often with out
- to act as a filter for
Origin of filterFr filtrer < the n.
- to pass through or as if through a filter
- to move or pass slowly: the news filtered through town
- 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.
- Computers A program or device that blocks e-mail or restricts website access when specific criteria are met.
verbfil·tered, fil·ter·ing, fil·ters
- To pass (a liquid or gas) through a filter.
- To remove by passing through a filter: filter out impurities.
- Computers To use a filter to block or restrict access to: a program that filters spam.
- 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 of filterMiddle English filtre, from Old French, from Medieval Latin filtrum, of Germanic origin; see pel-5 in Indo-European roots.
- 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.
- Electronics or software that separates unwanted signals (for example noise) from wanted signals or that attenuates selected frequencies.
- Any item, mechanism, device or procedure that acts to separate or isolate.
- He runs an email filter to catch the junk mail.
- (mathematics, order theory) A non-empty upper set (of a partially ordered set) which is closed under binary infima (a.k.a. meets).
- The collection of cofinite subsets of ℝ is a filter under inclusion: it includes the intersection of every pair of its members, and includes every superset of every cofinite set.
- If (1) the universal set (here, the set of natural numbers) were called a "large" set, (2) the superset of any "large" set were also a "large" set, and (3) the intersection of a pair of "large" sets were also a "large" set, then the set of all "large" sets would form a filter.
- (order theory): ultrafilter
(third-person singular simple present filters, present participle filtering, simple past and past participle filtered)
- To sort, sift, or isolate.
- To diffuse; to cause to be less concentrated or focused.
- (intransitive) To pass through a filter or to act as though passing through a filter.
- (intransitive) To move slowly or gradually; to come or go a few at a time.
- (intransitive) To ride a motorcycle between lanes on a road
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.
(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.