DM, or dm, stands for decimeters, which is a metric unit used for measuring length. A decimeter is equal to one tenth of a meter or 10 centimeters.
The metric system is the most widely used measuring system in the world. All major countries have adopted it except the United States. The system typically progresses in powers of 10. A decimeter is 10 times a centimeter, while a meter is 10 times a decimeter.
The metric system also contains units for weight in addition to length. The kilogram is the most common way to measure mass. There are 1,000 grams in a kilogram, as the prefix suggests.