Skip to Content


Pronunciation: fil'ter


  1. A porous substance through which a liquid or gas is passed to separate it from contained particulate matter or impurities to sterilize.
  2. To use or to subject to the action of a filter.
  3. In diagnostic or therapeutic radiology, a plate made of one or more metals such as aluminum and copper that, placed in the x- or gamma ray beam, permits passage of a greater proportion of higher-energy radiation and attenuation of lower-energy and less desirable radiation, raising the average energy or hardening the beam.
  4. A device used in spectrophotometric analysis to isolate a segment of the spectrum.
  5. A mathematical algorithm applied to imaging data for the purpose of enhancing image quality, usually by suppression or enhancement of high spatial frequencies.
  6. A passive electronic circuit or device that selectively permits the passage of certain electrical signals.
  7. A device placed in the inferior vena cava to prevent pulmonary embolism from low extremity clot. There are many variants.

Synonym(s): filtrum

[Mediev. L. filtro, pp. -atus, to strain through felt, fr. filtrum, felt]

Disclaimer: This site is designed to offer information for general educational purposes only. The health information furnished on this site and the interactive responses are not intended to be professional advice and are not intended to replace personal consultation with a qualified physician, pharmacist, or other healthcare professional. You must always seek the advice of a professional for questions related to a disease, disease symptoms, and appropriate therapeutic treatments.
© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.