Filter  —n. 1 porous device for removing impurities etc. From a liquid or gas passed through it. 2 = *filter tip. 3 screen or attachment for absorbing or modifying light, x-rays, etc. 4 device for suppressing unwanted electrical or sound waves. 5 arrangement for filtering traffic. —v. 1 (cause to) pass through a filter. 2 (foll. By through, into, etc.) Make way gradually. 3 (foll. By out) (cause to) leak. 4 allow (traffic) or (of traffic) be allowed to pass to the left or right at a junction. [germanic: related to *felt1]