Completion is the state of being finished or the act of finishing something. When you reach the completion of a book, you've read the final page. When a builder celebrates the completion of a house, every wall is painted, every fixture installed, and the keys are ready to hand over.

The word carries a sense of accomplishment and wholeness. There's a difference between abandoning a puzzle halfway through and working until its completion, when that last piece clicks into place. A runner who trains for months feels the satisfaction of a marathon's completion as they cross the finish line.

In school, you might track your completion of assignments or work toward the completion of a long research project. Video game players often aim for 100% completion, finding every hidden item and finishing every side quest. The word suggests actually achieving what you set out to do, reaching the intended end point.

Completion implies that something is now whole and done, not partial or unfinished. When contractors give a completion date, they're promising when the work will be fully done, not just mostly done. That sense of finality and achievement is what makes completion feel different from simply stopping or quitting.