Meterkelvin

Meterkelvin is a term used to describe a derived unit defined as the product of a length expressed in meters and a temperature expressed in kelvin. In theory, it has the dimension of length multiplied by temperature (L·Θ). The symbol for the unit is often written as m·K, though in practice the sequence mK is commonly associated with millikelvin, which can lead to confusion. Meterkelvin is not part of the International System of Units (SI) and is not recognized by the International Bureau of Weights and Measures (BIPM).

Meterkelvin does not correspond to a single physical quantity in the way that base or well-established derived units do. It is primarily a conceptual convenience for dimensional analysis in contexts where a quantity depends on both a distance scale and a temperature scale. For example, expressions that involve the product of a characteristic length and a temperature may be described informally using a meterkelvin, but only with explicit definition within a given context to avoid ambiguity.

In standard scientific practice, length and temperature are treated with separate SI units (meters and kelvin) and, where appropriate, through clearly defined derived quantities (such as thermal expansion coefficients or heat transfer rates). If meterkelvin is used, it should be accompanied by a precise, context-specific definition that specifies exactly what is being multiplied and how it should be interpreted.

Overall, meterkelvin remains a niche, non-standard unit rather than an established part of the SI system, and its use is limited to particular, explicitly defined scenarios.