Chemistryany substance, such as cloth, paper, or charcoal, through which liquid or gas is passed to remove impurities or to trap solids:The spring water goes through a filter before it is bottled.
Chemistryany device containing a substance for filtering.
Photographya lens screen of colored glass used in photography to control the color or to diminish the intensity of light.
v.
to remove by the action of a filter:[~ + object]The dehumidifier filters moisture out of the air.
to act as a filter for; to slow the passage of:[~ + object]The dehumidifier filters the air.
to pass or slip through slowly:[no object]Sunlight was filtering through the trees.
[no obj] to reach gradually:Day by day, news filtered out about the catastrophe.
Chemistryany 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.
Chemistryany 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.
Informal Termsa filter-tipped cigarette or cigar.
Photographya lens screen of dyed gelatin or glass for controlling the rendering of color or for diminishing the intensity of light.
Electronics, Physicsa circuit or device that passes certain frequencies and blocks others.
Mathematicsa 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.
v.t.
to remove by the action of a filter.
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.
v.i.
to pass or slip through slowly, as through an obstruction or a filter:Enemy agents managed to filter into the embattled country.
Gmc; see felt2
Medieval Latin filtrum felt, piece of felt used to strain liquids
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 See alsoband-pass filter
a computer program that processes data in order to remove items that correspond to certain criteria: a spam filter
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
Brita 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
a function of image-editing software that allows the user to alter a feature of a complete image, for example its colour
informala notional process by which a person is able to modify socially unacceptable thoughts into socially acceptable speech or behaviour
vb
(often followed by out) to remove or separate (suspended particles, wavelengths of radiation, etc) from (a liquid, gas, radiation, etc) by the action of a filter
(transitive) to obtain by filtering
(intransitive) followed bythrough: to pass (through a filter or something like a filter): dust filtered through the screen
(intransitive) to flow slowly; trickle
Etymology: 16th Century filtre from Medieval Latin filtrum piece of felt used as a filter, of Germanic origin; see felt2