What does "por" mean in ¿Por dónde camina usted?
Used in my textbook, not explained:
¿Por dónde camina usted?
What does "por" mean there? Machine translation ignores it.
Through is the usual translation.
Miro por la ventana. I am looking through the glass.
Anda por la puerta. Walk through the door(way).
Corre por el parque. He is running through the park.
Via would be another meaning or by way of.
In ¿Por dónde ...? you're asking "by what route are you going"?
the question is asking Where you will be walking or traveling? How (by what route) will you get there?
Voy a caminar por la ciudad. I'm going to walk around the town.