■ noun
1》 a porous device for removing impurities or solid particles from a liquid or gas passed through it.
↘a screen, plate, or layer which absorbs some of the light passing through it.
↘a device for suppressing electrical or sound waves of frequencies not required.
2》 Brit. 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.
3》 Computing a piece of software that processes data before passing it to another application, for example to remove unwanted material.
■ verb
1》 pass through a ~.
2》 (often ~ in/out/through ) move or pass into something slowly or gradually.
↘(of information) gradually become known.
Derivatives
~able (also filtrable ) adjective
Origin
ME (denoting a piece of felt): from Fr. filtre , from med. L. filtrum 'felt used as a ~', of W. Gmc origin and related to felt 1 .