<p><strong>Noun</strong></p><ul><li>any 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</li><li>any device, as a tank or tube, containing such a substance for filtering</li><li>any of various analogous devices, as for removing dust from air or impurities from tobacco smoke, or for eliminating certain kinds of light rays</li><li>something that works like a filter, as by removing, blocking, or separating out certain elements</li><li>an informal term for a filter-tipped cigarette or cigar</li><li>a lens screen of dyed gelatin or glass placed on a camera for controlling the rendering of color or for diminishing the intensity of light</li><li>a data manipulation function that changes the color or sharpness of a digital image or overlays an additive or special effect element</li><li>a circuit or device that passes certain frequencies and blocks others</li><li>a 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</li><li>an algorithm that categorizes, sorts, prioritizes, or blocks data through rule-based protocols</li></ul><p><strong>Verb</strong></p><ul><li>to remove by the action of a filter</li><li>to subject (data) to an algorithmic filter</li><li>to act as a filter for; to slow or partially obstruct the passage of</li><li>to pass through or as through a filter</li><li>to pass or slip through slowly, as through an obstruction or a filter</li></ul><p><strong>Synonyms</strong></p><ul><li>leak</li><li>trickle</li><li>seep</li><li>sift</li><li>penetrate</li></ul>