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Medical Term:


Pronunciation: ā′jent


  1. An active force or substance capable of producing an effect. For agents not listed here, see the specific name.
  2. In disease, a factor such as a microorganism, chemical substance, or a form of radiation, the presence or absence of which (as in deficiency diseases) results in disease or in more advanced form of disease.

[L. ago, pres. p. agens (agent-), to perform]

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