The Romanian equivalent for „кисело мляко“ is „lapte bătut” (buttermilk, this the name found on products in stores) or „lapte acru” (sour milk, regional, less commonly used) or „lapte prins” (bound milk, regional, even less commonly used; refers to sour milk becoming thicker than regular milk). The latter names are what your Romanian grandmother would call it, depending on the region. There is also „lapte covăsit” which is even less commonly used. It's derrived from the Ukrainian „квacити” which refers to the process of mixing a bit of „covăseală” (starter culture in the form of sour cream or sour milk) in regular milk in order to make sour milk. This name has been lately promoted by a dairy company in Covasna county because it sounds like its name.
Sour milk that you find in stores is usually a drinkable yoghurt that has more acidity than regular yoghurt. A good product would be a thick yoghurt drink with the consistence of a thick smoothie that's unevenly mixed and has a more acidic taste (much like ayran or kefir). Not to be confused with „iaurt de băut” (yoghurt drink) products which are a watered down variant of regular yoghurt with a boring, nondescript taste.
Sour milk that you find in stores is usually a drinkable yoghurt that has more acidity than regular yoghurt. A good product would be a thick yoghurt drink with the consistence of a thick smoothie that's unevenly mixed and has a more acidic taste (much like ayran or kefir). Not to be confused with „iaurt de băut” (yoghurt drink) products which are a watered down variant of regular yoghurt with a boring, nondescript taste.