A decimeter is a unit of length in the metric system, equal to one-tenth of a meter. It is commonly used in various fields, such as science and engineering, to measure shorter distances. The symbol for decimeter is "dm," and it is part of the International System of Units (SI). In practical terms, a decimeter is about the length of a large ruler or a small book. It helps provide a more precise measurement than centimeters or meters when needed. Understanding decimeters can be useful in everyday situations, such as cooking or crafting, where accurate measurements are important.