This is the 2nd most frequent Romanian word.
în
The Romanian word "în" means "in" or "into" in English.
Here, 'în' is used as a preposition to indicate location within a specific place.
Eu sunt în casă.
I am in the house.
In this sentence, 'în' expresses that the notebook is located inside the bag.
Caietul este în geantă.
The notebook is in the bag.
Here, 'în' is used to signify being engaged in an activity, here a vacation, during a certain time.