Completion/kəmˈpliːʃn/ Definition 1 of 3Pro Tip 1/3Time Requirement Emphasizes that something took a certain amount of effort and time to finish. After years of hard work, the completion of her thesis was a triumph. Pro Tip 2/3Project Milestone Often signals a significant achievement in a project or task's progression. The team celebrated the completion of the prototype with a small party. Pro Tip 3/3Projected End Used to estimate when a task or project is expected to be finished. The completion date for the new building is set for next June.