]> In common usage, a dimension is a parameter or measurement used to describe some relevant characteristic of an object. The most commonly used dimensions are the parameters describing the size of an object: length, width, and height, but dimensions can also be other physical parameters such as the mass and electric charge of an object, or even, in a context where cost is relevant, an economic parameter such as its price. A set of different forecasts all valid at the same forecast time(s). A forecast of weather conditions for a period extending beyond three or more days from the day of issuance.