1a porous device for removing impurities or solid particles from a liquid or gas passed through it:an oil filter
a filter tip: [as modifier]:a cheap filter cigarette
a screen, plate, or layer of a substance which absorbs light or other radiation or selectively absorbs some of its components:filters can be used in photography to reduce haze
a device for suppressing electrical or sound waves of frequencies not required.
Computing a piece of software that processes data before passing it to another application, for example to reformat characters or to remove unwanted types of material.
2British an arrangement whereby vehicles may turn left (or right) while other traffic waiting to go straight ahead or turn right (or left) is stopped by a red light: [as modifier]:a filter lane
a traffic light signalling a filter arrangement.
1 [with object] pass (a liquid, gas, light, or sound) through a device to remove unwanted material:the eye filters out ultraviolet radiation
process or assess (items) in order to reject those that are unwanted:you’ll be put through to a secretary whose job it is to filter callsthe brain has the ability to filter out information it considers non-essential
Computing process or treat with a filter.
2 [no object, with adverbial of direction] move slowly in a specified direction:the players filtered out on to the pitch
(of light or sound) enter a place slowly or in small quantities:sunlight filtered in through the thin curtains
(of information) gradually become known:the news began to filter in from the hospital
British (of traffic) be allowed to pass to the left or right at a junction while traffic going straight ahead is halted.