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

a computer program that processes data in order to remove items that correspond to certain criteria

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

a function of image-editing software that allows the user to alter a feature of a complete image, for example its colour

a notional process by which a person is able to modify socially unacceptable thoughts into socially acceptable speech or behaviour

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