Paint thinner is a type of SOLVENT used to thin oil-based paints and varnishes. The most common solutions for paint thinner are solvents such as turpentine, turps, and oil of turpentine. Turpentine is a colorless liquid distilled from the resin of certain pine trees and is composed of terpenes. Turps is a petroleum-based SOLVENT derived from turpentine and is used in many industrial applications. Oil of turpentine is a mixture of turpentine and other hydrocarbons that is used as a paint thinner and SOLVENT.