Nirvana literally means cooling off

Meditation

According to Karen Armstrong page 33, A History of God. 

The Guru Granth Sahib (GGS) talks a lot about "my mind (man) and Body (tan) becoming cool (seetal) 

When I was reading the GGS, I liked encountering the phrase "man tan seetal" 

It's that mellow feeling after a long period meditation.  It is as if desire heats up the brain and meditation cools it. It reminds me of when I was traveling in India and arrived in Amritsar with a pleasant 20 degrees centigrade.