opioid

  1. Noun.  A substance that is like opium.
  2. Noun.  (physiology) Any of the natural substances, such as an endorphin, released in the body in response to pain.
  3. Noun.  (pharmacology) Any of a group of synthetic compounds that exhibit similarities to the opium alkaloids that occur in nature.
  4. Adjective.  Pertaining to opioids.

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This entry was last updated on RefTopia from its source on 3/20/2012.