In cell culture biology, confluency is the term commonly used as a measure of the number of the cells in a cell culture dish or a flask, and refers to the coverage of the dish or the flask by the cells. For example, 100 percent confluency means the dish is completely covered by the cells, and therefore no more room left for the cells to grow; whereas 50 percent confluency means roughly half of the dish is covered and there is still room for cells to grow.