air cleaner, air filter - a filter that removes dust from the air that passes through it

bacteria bed - layer of sand or gravel used to expose sewage effluent to air and the action of microorganisms

coffee filter - filter (usually of paper) that passes the coffee and retains the coffee grounds

device - an instrumentality invented for a particular purpose; "the device is small enough to wear on your wrist"; "a device intended to conserve water"

drain basket - a filter in a sink drain; traps debris but passes water

filter bed - filter consisting of a layer of sand or gravel for filtering water

fuel filter - a filter in the fuel line that screens out dirt and rust particles from the fuel

diffusing screen, light filter - a transparent filter that reduces the light (or some wavelengths of the light) passing through it

oil filter - a filter that removes impurities from the oil used to lubricate an internal-combustion engine

strainer - a filter to retain larger pieces while smaller pieces and liquids pass through

water filter - a filter to remove impurities from the water supply

glass wool - glass fibers spun and massed into bundles resembling wool

diatomaceous earth, diatomite, kieselguhr - a light soil consisting of siliceous diatom remains and often used as a filtering material

electrical device - a device that produces or is powered by electricity

separate - divide into components or constituents; "Separate the wheat from the chaff"

penetrate, perforate - pass into or through, often by overcoming resistance; "The bullet penetrated her chest"

infiltrate - pass into or through by filtering or permeating; "the substance infiltrated the material"

infiltrate - cause (a liquid) to enter by penetrating the interstices

course, flow, run, feed - move along, of liquids; "Water flowed into the cave"; "the Missouri feeds into the Mississippi"

percolate, leach - permeate or penetrate gradually; "the fertilizer leached into the ground"