Suction Posted on 22nd December 20156th May 2021 by ThePD (The Project Definition) Suction is an act or process of flowing fluid into a partial vacuum or low pressure. 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 Engineering and tagged process. 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.