Sonic Posted on 21st December 20157th May 2021 by ThePD (The Project Definition) Sonic means sound or the speed at which sound travels in air, or the nature of sound or sound waves. 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 air, property. 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.