A point is a unit of measurement that is the standard for measuring type and is used for measuring depth of printing. One point is equal to .013836 of an inch and 72 points are approximately 1 inch. (72 points are actually .996264 inches)
For all practical type measurement purposes we round 72 points to 1 inch. When we take spacing above and below a line of type into consideration, when set at 72 points that line of type will take up approximately an inch of vertical space.