Diluent

1. n. An agent used for effecting dilution of the blood; a weak drink.
2. a. Diluting; making thinner or weaker by admixture, esp. of water.
3. n. That which dilutes.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.