thinner

noun2

1. •
   A liquid substance used to thin the consistency of another liquid.

   • Turpentine or mineral spirits can be used as a thinner for oil-based paints.
2. •
   Something that thins or thins out (another thing).

   • Pomegranate juice and exercise are great natural blood thinners.
   • The new type of mechanical thinner allowed thinning of peach blossoms to be completed earlier.