What is the difference between milk (simple) and milk drink? Here in Finland I have come across two types of milk. One is simple milk (maito/mjölk) and the other is milk-drink (maitojuoma/mjölkdryck). They also have variations like fat-free, light, whole (hel/täys) and lactose(-free).
Lactose-free whole milkdrink and whole milk, and light milkdrink and light milk have different tastes.
The difference between their ingredients is milk-based mineral preparations, mineral product or mineral preparations
Swedish:

mjölkbaserat mineralpreparat (Milbona)
mineralpreparat (Valio)

Finnish:

maitopohjainen kivennäisvalmiste (Milbona)
maitovalmiste (Valio)

They have different nutrition values but the same mineral value (only compared Milbona whole milk).
And both are placed in refrigerated compartments.
(I found milkdrink's taste slightly better.)
Question:
What is the differences between (simple) milk and milk-drink?
If the milk is modified by removing the lactose, it is no longer considered milk, and must be sold under a different name, such as milkdrink. The fat content can be modified while still considering it milk however.

The swedish FAQ of Valio (the biggest dairy producer in Finland) is very clear on this. 

http://www.valio.se/halsa/laktosintolerans/fragor-och-svar

I couldn't however find the same quote in the Finnish FAQ (Via google translate).

http://www.valio.fi/usein-kysytyt-kysymykset/

While the legislation could in theory be different between the two countries, I believe this is probably regulated on EU level.