Description
Ukonvasara - Ukko's Hammer - or Ukonkirves - Ukko's Axe - is the symbol and magical weapon of the Finnic thunder god. In Finnish mythology the thunder god is referred to with names Ukko, Äijä or Äijö and sometimes Ilmarinen. The Estonian parallel is Uku, Vanaisa - Grandfather - or Taevataat - Sky Father.
The name Ukko literally means old man in Finnish so it's possible that it is actually just an euphemism for the name Perkele - or some other name. On the other hand the Finnish word for thunder is Ukkonen which is the diminutive form of the name Ukko.
More info - Finnic History & Mythology:
www.fb.me/finnic.org / www.finnic.org