International Workers’ Day Posted on 1st December 20154th October 2020 by ThePD (The Project Definition) International Workers’ Day refers to the Labour (Labor) Day or May Day. 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 Controls and tagged calendar, schedule. 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.