noun

• (Greek mythology) The liquid said to flow in place of blood in the veins of the gods.
  "This ſaid, ſhe wip’d from Venus’ wounded Palm / The ſacred Ichor, and infus’d the Balm."
• (by extension)
  "He had merely meant to express his feeling that the streams which ran through their veins were not yet purified by time to that perfection, had not become so genuine an ichor, as to be worthy of being called blood in the genealogical sense."
• (by extension)
  "[I]chores and thoſe ſerious matters being thickned become flegme, and flegme degenerates into choler, choler aduſt becomes æruginoſa melancholia, as vinegar out of the pureſt wine putrified or by exhalation of purer ſpirits is ſo made, and becomes ſowre and ſharp; […]"
• (by extension)