This is the 1653rd most frequent Dutch word.
onderweg
On the way.
The word 'onderweg' is used as an adverb indicating that the subject is in transit to a specific place, in this case, school.
Ik ben onderweg naar school.
I am on my way to school.
Here, 'onderweg' describes the period or process of travel back home, indicating something happened during the journey.
Onderweg naar huis kwam ik een oude vriend tegen.
On the way home, I encountered an old friend.
In this sentence, 'onderweg' is used to suggest an action that can occur during a trip or journey.