A ratio of reduction between real world distances and distances on a map is called Map Scale.
The following three statements show the same scale:
1 inch = 2,000 feet
1 inch = 24,000 inches
The left side of the ratio is the distance on the map and the right side of the ratio is the distance on thesurface of the earth. When there are no units expressed in the ration, such as in 1:24,000, that means any unit on the map (e.g., 1 inch, a centimeter, or a foot) is equal to 24,000 units of that same size on the surfaceof the earth.