Any porous substance, as cloth, paper, sand, or charcoal, through which water or other liquid may passed to cleanse it from the solid or impure matter held in suspension; a chamber or device containing such substance; a strainer; also, a similar device for purifying air.
- 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 material, especially one used to extract impurities from air or water.
- Any of various electric, electronic, acoustic, or optical devices used to reject signals, vibrations, or radiations of certain frequencies while allowing others to pass.
- 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.