K

KELVIN K
The kelvin is the basic unit of temperature. It is 1/273.16th of the thermodynamic temperature of the triple point of water.

It is named after the Scottish mathematician and physicist William Thomson, first Lord Kelvin (1824-1907).
More on Lord Kelvin

KILO k
A metric prefix meaning 1000 or 10^3.

KILOGRAM kg
The kilogram is the basic unit of mass. It is the mass of an international prototype in the form of a platinum-iridium cylinder kept at Sevres in France.
It is now the only basic unit still defined in terms of a material object, and also the only one with a prefix [kilo] already in place.

kW
1000 watts. See Metric Prefixes

kWH
Kilowatt hours (kW times hours) A measurement of power and time used by utilities for billing purposes.