DACIA

Few know that the word has an alternative spelling - DATIA:
http://books.google.com.ua/books?id=1kOMSQnGm_cC&pg=PA196&lpg=PA196&dq=dacia+%22datia%22&source=bl&ots=7ztfU0FAlN&sig=3oWk5i7_2ZpkHG_TrZr7nSrnbkc&hl=uk&sa=X&ei=TShFU8CIKuil4ASPmYD4BA&ved=0CHwQ6AEwBw#v=onepage&q=dacia%20%22datia%22&f=false

...which explains a lot.

First, we can make sure now that the toponym is also of Kartvelian toponymic origin:
DATIA (Laz.) = DETIA (Kart.) = დეთი = 'land of Da/De'.

What is 'de' or 'da'? Unlikely that it's 'sister' (although, who knows). But definitely it's the Perisan tribe 'Dai' mentioned by Herodotus together with 'Derusiei' and 'Germanii'.

So, now we know (1) 'Dacia' is a Kartvelian word too; and (2) Daci were indeed Indoeuropean.