1A porous device for removing impurities or solid particles from a liquid or gas passed through it.

1. 1.1 A filter tip.
   as modifier a cheap filter cigarette

   Example sentencesExamples

   • You'd think that not having to add a filter would make the cigarette cheaper, but that doesn't seem to be the case.
   • This involved tearing off the filter portion of each cigarette and heaping them on a non-stick oven sheet.
   • She broke the filter off her cigarette then licked and split it down the paper join.
   • The filters attach to cigarettes and gradually reduce the amount of nicotine consumed.
   • The material was sprayed onto buildings, used in shipyards, it covered pipes, was weaved into cloth and was even placed in cigarette filters.
   • The company, which makes products as diverse as plastic caps and cigarette filters to food packing and carrier bags, is expected to post in-line figures.
   • Cigarette filters, which can last up to 100 years - are designed to absorb tar and other chemicals from the cigarette.
   • The air possessed a pungent, acrid smell because the cigarette had burned through a filter stub in the overflowing ashtray.
   • This been accomplished by the use of filters and filter ventilation, modified cigarette paper and modified forms of tobacco and tobacco blends.
   • According to experts in the field of industrial deafness, the current methods of hearing protection such as ear muffs and plugs are about as effective as filters on cigarettes.
   • This will bring the price of a standard pack of filter cigarettes to 4.15.
   • The cigarette has a filter that makes them harder to inhale, aimed at reducing tar and nicotine consumption.
   • US studies have suggested that the shift of longstanding smokers to low tar filter cigarettes results in the smoker inhaling more deeply and retaining smoke longer.
   • It would almost be like smokers 50 years ago trying to get tobacco companies to pay to put filters on all cigarettes, just in case the products turned out to be dangerous.
   • Dougal took his final drag and stared at the cigarette filter for a few seconds before tossing it over the railing, down to the earth below.
   • Therefore, inhaled tobacco smoke without a filter contains as much as four times more nicotine as a regular filtered cigarette.
   • And the problem was he was smoking those terrible cigarettes without filters.
   • Like, twenty plastic bags filled with those cigarette filters.
   • The company also makes cigarette filters, ink reservoirs and self-adhesive tear tapes.
   • She breathed in my ear, sipping her coffee and smoking one of those cigarettes with the big filters.
2. 1.2 A screen, plate, or layer of a substance which absorbs light or other radiation or selectively absorbs some of its components.
   filters can be used in photography to reduce haze

   Example sentencesExamples

   • If you must shoot with it, you can use a light pink FLD filter with daylight films to remove some of the greenish cast.
   • Sony's trick is to apply an anti-glare filter to the screen that doesn't scatter light the way other filters do.
   • I have tried to get these bright and vibrant colors with a polarizer filter but the colors were not enough.
   • In the eleventh century he did not have the advantage of either a telescope to project an image safely onto a screen or optical filters.
   • As a serious photography project, this is one time you do not need wide angle lenses, special filters or off camera flash guns.
   • This opening was then covered with one to six layers of neutral-density filters made from a sheet of developed X-ray film.
   • The vain portrait sitter certainly won't mind if a wrinkle or two is removed by the use of a soft focus filter of a bit of silk in front of the lens.
   • You can use this haze to advantage, but if it is obscuring your subject, you may need to place a filter over your SLR lens.
   • Thinking that his telescope or filter was allowing light to leak into the projected image, he adjusted his instrument.
   • The anti-alias filter sits between the lens and the mirror and can be removed if required by removing a two small screws.
   • The beam output was not lowered because it burned through the neutral density filters.
   • A screen on the light box filters out ultraviolet rays.
   • Cinematography is the technical craft of shooting a film: the camera, lens, film, filters, framing, etc.
   • A wavelength range between 350 and 800 nm was selected by optical filters.
   • To cut down on the glare, he used a polarized filter on his camera.
   • Without their UV-blocking filters, quartz halogen lamps were observed to emit wavelengths even shorter than 250 nm.
   • Soft-focus or diffusion filters give a misty quality to images and can impart a romantic mood to scenics and flower close-ups.
   • However, many species then alter the spectra of the emitted light using spectral filters and reflectors.
   • But there are more varieties of soft focus filters than there are adjectives describing them.
   • Digital cameras can also mount filters, auxiliary lenses and polarizers allowing you to meet any photographic challenge you might come across with.

   Synonyms

   sieve, riddle, sifter, strainer, colander, filter, winnow
3. 1.3 A device for suppressing electrical or sound waves of frequencies not required.
   Example sentencesExamples

   • The screen print in Figure 10 shows the swept frequency response of the low-pass filter.
   • Passive components are capacitors, resistors, connectors, filters, inductors, and oscillators.
   • However, replacing the analog filter with a digital filter requires a very precise converter.
   • Only very high-end receivers will provide the filters for all signals.
   • A spectral analysis of this summed pattern is next performed by a set of bandpass spatial frequency filters.
   • If one of the two obviously is higher than the other, adjust the related frequency filters as needed.
   • Many digital speaker processors, which are often used primarily as crossovers, also include filters for frequency correction.
   • Crosstalk from synchronizing signals is suppressed by filters.
   • We did this by assessing the performance of both filters in filtering noise signals obtained from both habitats throughout the breeding season.
   • The digital filter operated in the frequency domain employing an inverse Fourier algorithm.
   • The second image-analysis method uses a 2-D frequency band-reject filter.
   • Finally, consider the wavelengths that are attenuated by the filter.
   • The extremely narrow lines of the solar spectrum require filters with correspondingly high resolution.
   • The filter's feedback implementation compensates for strapdown navigation error and sensor errors.
   • An electronic filter prevents frequencies from reaching the speakers that are not supposed to receive them.
   • The input signal must be of a specific frequency to be conducted through the filters and of specific amplitude to overcome the offset.
   • Rectifiers and trap filters are strongly recommended on all variable frequency drives.
   • I could go hotter, but the filters in ADCs require 1 to 2 dB of headroom and you may want your mastering engineer to have some room to work, too.
   • Product groups include passive and electromechanical components, capacitors, resistive products, ferrites, fuses, inductors and filters.
   • A second bandpass filter with a center frequency above the fundamental can be used as the pulse generator.
4. 1.4Computing (in image-editing software) a function used to alter the overall appearance of an image in a specific manner.
   many other apps also offer filters for enhancing photos
5. 1.5Computing A piece of software that processes data before passing it to another application, for example to reformat characters or to remove unwanted types of material.
   Example sentencesExamples

   • Requiring filters would have just made people even less likely to keep an eye on what people on those computers were doing - and could also block out perfectly legitimate sites.
   • That will speed up download times and should allow software filters to be reinstalled, to the relief of teachers and parents.
   • Mr Porter said such filters had been removed because they slowed down access to the Internet.
   • Most search engines have duplication filters in effect that look past formatting changes and do a very good job of detecting duplicate content.
   • While half the respondents have Internet access, only a third use software filters to block racy or undesirable Web sites.

2British An arrangement whereby vehicles may turn left (or right) while other traffic waiting to go straight ahead or turn right (or left) is stopped by a red light.

1. 2.1 A traffic light signalling a filter arrangement.
   Example sentencesExamples

   • Good news for motorists - a filter light for traffic existing from Athy Road on to the Main Street is also in the pipeline.
   • Then, curiously, a leftturn filter arrow was installed at the traffic lights, replacing a ‘yield’ sign.
   • Why do so many traffic lights not have right turn filters, and why does the filter at Over Hulton never work?
   • In it I was assured that plans were in hand to install a right-turn filter once necessary ducting work had been completed.
   • Several traders suggested introducing a green filter at the traffic lights in Cricklade Road to allow cars to turn right easier.

1with object Pass (a liquid, gas, light, or sound) through a device to remove unwanted material.

1. 1.1 Process or assess (items) in order to reject those that are unwanted.
   you'll be put through to a secretary whose job it is to filter calls

   the brain has the ability to filter out information it considers non-essential
2. 1.2Computing Process or treat with a filter.
   Example sentencesExamples

   • Some of you said we're overplaying the privacy concerns involved in trusting ISPs or managed services providers to filter malicious messages from email traffic.
   • Of course, users may be tempted to filter all server error messages, but that's not a reliable solution because doing so would also block legitimate mail server error messages.
   • It they're in my way then search engines should filter them.
   • Alas, search engines have always filtered by structure, rather than the message, and so they should.
   • There's really no good reason to get caught out: simply filtering executable attachments from emails will guard against this virus.

2no object, with adverbial of direction Move slowly in a specified direction.

1. 2.1 (of light or sound) enter a place slowly or in small quantities.
   sunlight filtered in through the thin curtains

   Example sentencesExamples

   • Ryan's door was still shut, though there was some light filtering under his door.
   • Removing the glass from my lips, I looked over at the kitchen window which was gently filtering the moonlight from outside: the only source of light in the room.
   • Yesterday morning was beautiful, the sky was bright blue, it was warm and the sounds filtering into our home were happy.
   • As the sunshine filtered in, a new light came to her face and she sat in all her glory.
   • I felt exhausted and the moonlight slowly filtering through the window and covering everything only reinforced that.
   • Their voices filter through the branches like dust.
   • Sunlight filtered down through the canopy, falling warmly on her face as she walked beneath the trees.
   • As the morning passed, and the sun rose higher in the sky, dappled rays of sunlight filtered through the dense canopy of the jungle, creating dancing patterns on the floor.
   • He tried hard not to look like a fox, and gazed nonchalantly up to where brief rays of sunlight filtered through the branches of nearby oak trees and onto the decayed husks of dead bluebells.
   • The only light that filtered into the room came from two windows to her left.
   • The drawn curtains filtered the faint light with a slight red glow.
   • From the window filtered the first lights of the morning and hours had passed.
   • Light was filtering in through the dusty windows, as impossible as it seemed.
   • I had a feeling as the first light filtered through the elms across the road that it might be a pleasant morning.
   • Just then a loud crackling came over the speakers followed by the loud beating of a drum as the heavy rock music slowly filtered out into the car.
   • With a sigh she looked up, propping her head on one hand and watching dust motes dance in the rays of sunlight filtering down from above.
   • The metal roofing was added to the structure in 1894, and there is a hole under the dome to allow the sun to filter in.
   • Bright sunlight filtered down through the trees in patches.
   • Little rays of sunlight filtered through the curtains that were changed overnight.
   • Only faint rays of sunlight filtered through the thick leaves overhead.

   Synonyms

   seep, percolate, leak, trickle, ooze, dribble, bleed, flow
2. 2.2 (of information) gradually become known.
   the news began to filter in from the hospital

   Example sentencesExamples

   • The ideologies we live by are often made visible and comprehensive through the stories filtering into general consciousness.
   • Gradually the news filtered through that the latest incidents were nowhere near as bad as the bombings a fortnight ago.
   • Slowly it filtered out that they not doing very well and had sustained casualties.
   • But he had a belief on Cup final day that his team were going to win which filtered through to the players and we got the victory.
   • The book was timely, arriving at a time when youth culture was just kicking off in Britain, and linked nicely with the existentialist thought slowly filtering in from France.
   • Then the information filtered through to East End Park that Gary Holt had been called up to the international squad.
   • The critical demolition of it filtered into popular consciousness and it became the archetypal bad film.
   • An open management style will encourage communication and allow ideas to filter through from all levels of the organisation.
   • Then, finally, he held her chin, gently, so that his eyes bored directly into hers, and the words started to filter through.
   • News filtered through that the march had been cancelled after the skirmishes in Stirling.
   • News filtered through as MPs debated the bill that will pay for the Olympic Games.
   • ‘The more information filtering through to the workplace the better off we are all going to be,’ Brem says.
   • You probably could hear it, as word filtered back that he was in U.S. hands.
   • But as the news filtered out, the presidential palace began to be inundated with phone calls expressing disquiet.
   • Information has filtered out that the affected communities were provided next to no compensation and in some cases, were simply left at the mercy of floods.
   • I feel sure that many of our senior readers will recall where they were on that very sad Sunday evening as news of death filtered through.
   • She was in Portsmouth when news filtered through that the war in Europe was over.
   • While there has been no word from her, the woman believes information will filter through to the foreign country she is living in.
   • News of the move has filtered through the Northern Ireland political system as the British government has briefed local parties on developments as they unfold.
   • At that stage, death and what it meant had only just begun to filter into my consciousness.
3. 2.3British (of traffic) be allowed to pass to the left or right at a junction while traffic going straight ahead is halted.
   Example sentencesExamples

   • The problem with the whole system is it is putting too much pressure on Main Street as the traffic cannot filter through New Street anymore.
   • At 8am, traffic filtered around the closed-off Cricklade Street smoothly, but as the morning wore on, vehicles began to build up in Devizes Road and Albert Street.
   • She said new traffic lights were helping Park & Ride motorists as they filtered on to the A19 towards the roundabout, at the expense of people already on the A19.