Naming conventions aren't all that clear, but here are my rules of thumb:
Field Jacket - medium weight, general seasonal use, no hood (or if it has one it's hidden or detachable)
Parka - heavier weight, used only for winter, hood, generally thigh length
There are so many different things out there it's really not possible to generalize them accurately. To one collector a jacket is a parka, to another it is a smock, to another it's a coat, etc. Another way of saying "your milage may vary"
The Jugoslav items I'm familiar with make me think of this thing as a Field Jacket. But it's not something I'm familiar with so without seeing the other items issued alongside it I can't say for sure.