A decilitre is a metric unit of volume that is equal to one-tenth of a litre. It is commonly used in cooking and food labeling to measure liquids. For example, a recipe might call for 2 decilitres of milk, which is equivalent to 200 millilitres. In the metric system, the decilitre is abbreviated as "dL." It is part of a larger system that includes other units like millilitre and litre. Understanding decilitres can help in accurately measuring ingredients for recipes or understanding nutritional information on food packaging.