Elixir

A magical or medicinal potion believed to cure illness or grant immortality; a solution used in medieval alchemy.

From Arabic al-iksīr, itself borrowed from Greek xērion meaning 'powder for drying wounds.' The Arabic definite article 'al-' became permanently attached to the word. It entered Medieval Latin as elixir through translations of Arabic alchemical texts in 12th-century Spain, then passed into Old French and Middle English by the 14th century.