Axis Posted on 2nd November 201517th July 2021 by ThePD (The Project Definition) An Axis is a reference line which defines coordinates through the centre of an object. 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 basis. 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.