"Avenue" translates to "boulevard"? I wouldn't call myself an expert in that area but I think of a boulevard as a street with multiple lanes and an avenue as a 2 lane one... and "boulevard" is already a word in English which makes it even more confusing
In English, an avenue is a street lined with trees, whereas a boulevard is a street lined with bushes, flowers or trees. So all avenues are boulevards but not all boulevards are avenues. I don't know if Danish makes that distinction.