Ash Posted on 2nd November 201517th July 2021 by ThePD (The Project Definition) Ash is an inorganic residue that remains from burning combustible material. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Substance and tagged solid, substance. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.