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Pronunciation: im-presh'un


  1. A mark seemingly made by pressure of one structure or organ on another, seen especially during cadaveric dissections. See also groove for the various impressions of the lungs, descending aorta, subclavian artery, and vena cava.
  2. An effect produced on the mind by some external objects acting through the organs of sense.
  3. An imprint or negative likeness; especially, the negative form of the teeth and/or other tissues of the oral cavity, made in a plastic material that becomes relatively hard or set while in contact with these tissues, made to reproduce a positive form or cast of the recorded tissues; classified, according to the materials of which they are made, as reversible and irreversible hydrocolloid impression, modeling plastic impression, plaster impression, and wax impression.

Synonym(s): impressioTA

[L. impressio, fr. im- primo, pp. -pressus, to press upon]

Further information

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© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.