fil·ter (fĭlˈtər)

1. A porous material through which a liquid or gas is passed in order to separate the fluid from suspended particulate matter.
2. A device containing such a substance.
3. Any of various electric, electronic, acoustic, or optical devices used to reject signals, vibrations, or radiations of certain frequencies while passing others.
4. A translucent screen, used in both diagnostic and therapeutic radiology, that permits the passage of rays having desirable levels of energy.
5. A device used in spectrophotometric analysis to isolate a segment of the spectrum.

1. To pass a liquid or gas through a filter.
2. To remove by passing through a filter.
3. To pass through or as if through a filter.