Noun (compound word):
Tonttupaja refers to ”elves workshop” or what’s often called ”Santa’s workshop.”
It comes from ”tonttu” which means elf (in this case, one of Santa’s helpers), and ”paja” which means 1. smithy, forge, 2. workshop or 3. (slang) workplace.
You might hear ”Olin pajalla koko viikonlopun” to mean ”I spent the whole weekend at work.”