The hole or pocket, which has a diameter of 4 1/4 inches (10.8 cm) and a depth of at least 4 inches (10.2 cm), is the cylindrical hollow on the green (see there) into which the ball must be played. The flag is placed in the middle of the hole so that players can see where the hole is from a distance. A hole is also the name given to each individual fairway in itself. There are usually 18 holes per course.
