diluent /ˈdɪljuənt/noun 3adjective 1forms 3 noun3 •That which dilutes. •A solvent or other liquid preparation used to dilute a sample prior to testing. •An agent used for effecting dilution of the blood; a weak drink. adjective1 •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 formsdiluents · more diluent · most diluent