Definition of "alchemy"

alchemy

/ˈælkəmi/

noun
countable and uncountable, plural alchemies
1. (uncountable) The premodern and early modern study of physical changes, particularly in Europe, Arabia, and China and chiefly in pursuit of an elixir of immortality, a universal panacea, and/or a philosopher's stone able to transmute base metals into gold, eventually developing into chemistry.
  Quotations
  And yet surely to alchemy this right is due, that it may be compared to the husbandman whereof Æsop makes the fable; that, when he died, told his sons that he had left unto them gold buried underground in his vineyard; and they digged over all the ground, and gold they found none; but by reason of their stirring and digging the mould about the roots of their vines, they had a great vintage the year following: so assuredly the search and stir to make gold hath brought to light a great number of good and fruitful inventions and experiments, as well for the disclosing of nature as for the use of man’s life.
  1605, Francis Bacon, The Advancement of Learning‎, IV. (11)
  The [Isaac] Newton that emerges from the [unpublished] manuscripts is far from the popular image of a rational practitioner of cold and pure reason. The architect of modern science was himself not very modern. He was obsessed with alchemy.
  2014 June 21, “Magician’s brain”, in The Economist, volume 411, number 8892
2. (countable) The causing of any sort of mysterious sudden transmutation.
  Quotations
  O, he sits high in all the people’s hearts:And that which would appear offence in us,His countenance, like richest alchemy,Will change to virtue and to worthiness.
  1599 (first performance), William Shakespeare, “The Tragedie of Iulius Cæsar”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene iii]
  No alchymy to saving.
  1640, George Herbert, Jacula Prudentum; or, Outlandish Proverbs, Sentences, etc., in The Remains of that Sweet Singer of the Temple George Herbert, London: Pickering, 1841, p. 143
  Then of their session ended they bid cryWith trumpet’s regal sound the great result:Toward the four winds four speedy CherubimPut to their mouths the sounding alchemy,By herald’s voice explained; the hollow AbyssHeard far and wide, and all the host of HellWith deafening shout returned them loud acclaim.
  1667, John Milton, “Book II”, in Paradise Lost. […], London: […] [Samuel Simmons], […]; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873,
  [Poetry] transmutes all that it touches, and every form moving within the radiance of its presence is changed by wondrous sympathy to an incarnation of the spirit which it breathes: its secret alchemy turns to potable gold the poisonous waters which flow from death through life; it strips the veil of familiarity from the world, and lays bare the naked and sleeping beauty, which is the spirit of its forms.
  1840, Percy Bysshe Shelley, A Defence of Poetry‎
  There is such a rich thesaurus now of things that I have said that have been, one way or another, through what alchemy I do not know, somehow misconstrued, that it would really take me too long to engage in a full global itinerary of apology to all concerned.
  2016, Boris Johnson, (Please provide the book title or journal name)
3. (computing, slang, countable) Any elaborate transformation process or algorithm.