-AR SUFFIX

The official story is like this:
http://en.wiktionary.org/wiki/-ar

It's not interesting, since the etymology of '-ar' meaning 'place of...' is not given there. Just two such Spanish instances mentioned: sandiar and habar. We'll add to them also palmar and olivar: places of sandia, haba, palma and oliva.

The same has preserved in Ukrainian/Russian languages too: словарь [slovar], 'dictionary'; and букварь [bukvar], ABC book; being places of words and letters correspondingly.

Where does the suffix IN THIS VERY MEANING originate from?

It's Svan:
http://rino-ceronte.livejournal.com/272022.html?thread=816022

I don't know if Georgians already know about this, but this suffix leads to fancy origin of the word ზამთარი [zamtari] - 'winter'. The -ar suffix explains the word as 'place of zamti'. The word 'zamti' does not exist, but the word 'zamati' (ზამათი) exists perfectly well meaning 'mixed weather'. The omittance of a root vowel is an absolutely wide-spread practice in Kartvelian, so we end up with a wonderful etymology of ზამთარი (winter) as 'place of mixed weather'.

Needless to say that 'zamati' and 'zamtari' undoubtedly lead to Ukrainian/Russia 'zima' (winter) too.