PKW is a term that can have different meanings depending on the context. Here are some possible meanings:

• pKw: This is a measure used in chemistry to indicate the acidity or basicity of a solution. It is the negative logarithm of the equilibrium constant for the autoionization of water, Kw. At standard temperature, pKw should always equal 14, and Kw=10^-14.

• PKW Logistik Iberia: This is the name of a Madrid-based company that specializes in logistics and national and international transport.

• PKW: This is the name of a German car classification that stands for "Personenkraftwagen," which means "passenger car" in English.

Based on the search results, it seems that PKW is not a commonly used term in chemistry, and its meaning is usually specified as pKw.