filter

1 of 2

noun

fil·​ter ˈfil-tər 

1

a

: a porous article or mass (as of paper or sand) through which a gas or liquid is passed to separate out matter in suspension

b

: an apparatus containing a filter medium

2

a

: a device or material for suppressing or minimizing waves or oscillations of certain frequencies (as of electricity, light, or sound)

b

: a transparent material (such as colored glass) that absorbs light of certain wavelengths or colors selectively and is used for modifying light that reaches a sensitized photographic material

called also color filter

3

: something that has the effect of a filter (as by holding back elements or modifying the appearance of something)

his work is too often viewed through the filter of race

—Brent Staples

4

: software for sorting or blocking access to certain online material

filter

2 of 2

verb

filtered; filtering ˈfil-t(ə-)riŋ 

transitive verb

1

: to subject to the action of a filter

2

: to remove by means of a filter

intransitive verb

1

: to pass or move through or as if through a filter

2

: to come or go in small units over a period of time

people began filtering in

Synonyms

Verb

• screen
• strain

Examples of filter in a Sentence

Noun

She smokes cigarettes with filters.

He placed a red filter on the camera lens.

digital filters that stop high-frequency sounds

Verb

They've begun filtering their water to remove impurities.

a device that filters impurities from water

sunglasses that filter ultraviolet light

Sunlight filtered through the leaves.

His ideas have filtered down to his children.

The crowd filtered into the arena.

Early election returns have begun to filter in.

Recent Examples on the Web

Noun

Given that the federal rule will take several years to go into effect, Rumpler recommends that people concerned about PFAS in their drinking water buy a filter designed to catch the chemicals. —Kaitlin Sullivan, Health, 20 Apr. 2024

Some refrigerators also are equipped with water filters that can remove or reduce PFAS. —Mary Divine, Twin Cities, 18 Apr. 2024

Each pixel has a colored filter over it (either red, green, or blue), which only allows specific wavelengths of light to go through. —Briley Lewis, Popular Science, 18 Apr. 2024

From the ceiling of that small, carpeted room, theater lights treated with red and blue filters combine to throw auras of deep magenta on opposing walls. —Walker Mimms, New York Times, 17 Apr. 2024

Look for hotels or Airbnbs with flexible cancellation policies; sites like Travelocity have filters for exactly this. —Ashlea Halpern, Condé Nast Traveler, 16 Apr. 2024

That music gets enhanced by JBL's signature Pure Bass Sound and active noise cancelling that filters out surrounding distractions and creates an immersive listening experience. —Stackcommerce Team, PCMAG, 15 Apr. 2024

Mike Evans, the district’s chief technology and information officer, said the district tries to apply filters fairly. —Tara García Mathewson, USA TODAY, 13 Apr. 2024

Experts say these filters can be effective at reducing PFAS and other contaminants. —Michelle Marchante, Miami Herald, 11 Apr. 2024

Verb

After being gently heated and stirred for up to 14 hours, the mixture is filtered and cooled. —Leah Collins, CNN, 12 Apr. 2024

Their bottles are easy to pack away and can filter out 99.9% of harmful contaminants in most water sources. —Christopher Murray, Fox News, 11 Apr. 2024

Economists expect rent increases to moderate, based on new leases, but that has filtered through just gradually to existing leases. —Paul Davidson, USA TODAY, 10 Apr. 2024

There are several technologies available to purchase to filter PFAS from your home water source. —Tracy J. Wholf, CBS News, 10 Apr. 2024

The unit uses investigative journalism, technical skills, data and other tools to filter through content and determine what is real, and what isn’t, and to explain it to viewers. —Alex Weprin, The Hollywood Reporter, 9 Apr. 2024

Colman envisions a world where scanning for deepfakes is just a regular part of a computer’s cybersecurity software, in the same way that email applications like Gmail now automatically filter out obvious spam. —Gerrit De Vynck, Washington Post, 5 Apr. 2024

Israel said the coordinates never filtered down to the drone operators who fired the missiles. —Tracy Wilkinson, Los Angeles Times, 5 Apr. 2024

On the morning of Sept. 11, Al-Halabi was at breakfast at Travis when word of the attacks filtered out. —Tamara Audi, New York Times, 4 Apr. 2024

Word History

Etymology

Noun

Middle English filtre "felt, felt carpet, piece of felt used as a filter," borrowed from Medieval Latin filtrum "felt cloth, cover or blanket of felt, piece of felt used as a filter," borrowed from *filtir (going back to *filtizō) in a West Germanic language, plural of *filt-, *felt- "felted cloth" — more at felt entry 1

Verb

derivative of filter entry 1

First Known Use

Noun

15th century, in the meaning defined at sense 1a

Verb

1576, in the meaning defined at transitive sense 1

Phrases Containing filter

• band-pass filter
• color filter
• filter bed
• filter bubble
• filter feeder
• filter paper
• filter tip
• spam filter

Kids Definition

filter

1 of 2 noun

fil·​ter ˈfil-tər 

1

: a substance with pores through which a gas or liquid is passed to separate out floating matter

2

: a device containing a filter

3

: a transparent material (as colored glass) that absorbs light of some wavelengths and is used to change light (as in photography)

filter

2 of 2 verb

filtered; filtering -t(ə-)riŋ 

1

: to expose to the action of a filter

2

: to remove by means of a filter

3

: to pass through or as if through a filter

Medical Definition

filter

1 of 2 noun

fil·​ter ˈfil-tər 

1

: a porous article or mass (as of paper or sand) through which a gas or liquid is passed to separate out matter in suspension

2

: an apparatus containing a filter medium

3

a

: a device or material for suppressing or minimizing waves or oscillations of certain frequencies (as of electricity, light, or sound)

b

: a transparent material (as colored glass) that absorbs light of certain wavelengths or colors selectively and is used for modifying light that reaches a sensitized photographic material

called also color filter

filter

2 of 2 verb

filtered; filtering -t(ə-)riŋ 

transitive verb

1

: to subject to the action of a filter

2

: to remove by means of a filter

intransitive verb

: to pass or move through or as if through a filter