- any substance, as cloth, paper, porous porcelain, or a layer of charcoal or sand, through which liquid or gas is passed to remove suspended impurities or to recover solids.
- any device, as a tank or tube, containing such a substance for filtering.
- any of various analogous devices, as for removing dust from air or impurities from tobacco smoke, or for eliminating certain kinds of light rays.
- something that works like a filter, as by removing, blocking, or separating out certain elements: Kids often talk without a filter. Events can be distorted through the filter of memory.
- a filter-tipped cigarette or cigar.
- Photography.
- a lens screen of dyed gelatin or glass placed on a camera for controlling the rendering of color or for diminishing the intensity of light.
- a data manipulation function that changes the color or sharpness of a digital image or overlays an additive or special effect element: Use a sepia filter to give your photos that old-timey look.
- a circuit or device that passes certain frequencies and blocks others.
- a collection of subsets of a topological space, having the properties that the intersection of two subsets in the collection is a subset in the collection and that any set containing a subset in the collection is in the collection.
- an algorithm that categorizes, sorts, prioritizes, or blocks data through rule-based protocols: an email filter that deletes messages with subject words found commonly in spam.
- to remove by the action of a filter.
- to subject (data) to an algorithmic filter: The search engine will filter your query results based on your location and user profile.
- to act as a filter for; to slow or partially obstruct the passage of: The thick leaves filtered the sunlight.
- to pass through or as through a filter.
- to pass or slip through slowly, as through an obstruction or a filter: Enemy agents managed to filter into the embattled country.
- a porous substance, such as paper or sand, that allows fluid to pass but retains suspended solid particles: used to clean fluids or collect solid particles
- any device containing such a porous substance for separating suspensions from fluids
- any of various porous substances built into the mouth end of a cigarette or cigar for absorbing impurities such as tar
- any electronic, optical, or acoustic device that blocks signals or radiations of certain frequencies while allowing others to pass
- any transparent disc of gelatine or glass used to eliminate or reduce the intensity of given frequencies from the light leaving a lamp, entering a camera, etc
- a traffic signal at a road junction consisting of a green arrow which when illuminated permits vehicles to turn either left or right when the main signals are red
- to remove or separate (suspended particles, wavelengths of radiation, etc) from (a liquid, gas, radiation, etc) by the action of a filter
- to obtain by filtering
- to pass (through a filter or something like a filter)
- to flow slowly; trickle
