Diluent /(?)/

Dil·u·ent

Diluent

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

Diluent

n.
  1. That which dilutes.
  2. An agent used for effecting dilution of the blood; a weak drink. (Med.)
    There is no real diluent but water.