diluent

plural diluents

1. That which dilutes.
2. analytical chemistryA solvent or other liquid preparation used to dilute a sample prior to testing.
3. medicineAn agent used for effecting dilution of the blood; a weak drink.

   But the case was pressing, and the nearest medical practitioner was sent for. On examining the throat, he expressed his desire that a physician should be called in, and accordingly a gentleman, duly authorized, made his appearance, and prescribed gargles and diluents secundem artem.

   1842, [anonymous collaborator of Letitia Elizabeth Landon], chapter XXIV, in Lady Anne Granard; or, Keeping up Appearances. […], volume II, London: Henry Colburn, […], →OCLC, pages 230-231

comparative more diluent · superlative most diluent

1. Diluting; making thinner or weaker by admixture, especially of water.

   there is no real Diluent but Water, every Fluid is diluent as it contains Water in it

   1731, John Arbuthnot, An Essay Concerning the Nature of Aliments, and the Choice of Them, According to the Different Constitutions of Human Bodies. […], London: […] J[acob] Tonson […], →OCLC