Gantt chart

Definition
A Gantt chart is

"a horizontal bar chart that graphically displays time relationships. In effect, it is a "scale" model of time because the bars are different lengths depending upon the amount of time they represent."

Overview
It is named after Henry Laurence Gantt, the American engineer and social scientist who first developed it. Gantt charts have been around since the early 1900s and are frequently used in business to plan and manage large projects.