Kelvin is a unit of measurement for temperature. It was named after Scottish physicist William Lord Kelvin, who wrote about the need for an absolute thermometric scale. It's symbol is K.
There is also a Kelvin circulation theorem, a Kelvin equation, and Kelvin functions.
Kelvin is an English name meaning 'friend of ships.' I think that K would be a great nickname since it's also the symbol for the unit of temperature. Kelvin has been in the top 1,000 names in the U.S. since 1950. It's been declining in popularity. In 2014, it was the 684th most popular name.