Ghiozdan - Bookbag is the only option?
Sounds somewhat weird to me ... 'in the schoolbag'. Any native english speakers around?
yep weird. at least 'in my schoolbag'...
What is the difference between schoolbag and the schoolbag?
Remember that you drop the article after a presposition as long as the noun is not further modified.
For it to read "in a schoolbag" it has to be "într-un ghiozdan".