As mentioned by lorua, it leads us to 'tusen takk' which could be translated as 'many thanks' or literally 'thousand thanks'.
I think it's even more common than just 'takk'. At least that's how I remember it from visiting Norway 3 years ago. Things could have changed since then!
"Tusen takk"It would translate: "Thank you very much!"
In German there is the same expression: "Tausend Dank" but it's a little old fashioned, not so common anymore and more used in the south inkl Switzerland and Austria.