At the junction means where two or more roads meet. Turn left at the junction, wait at the junction.
It is the standard landmark in directions because it is a decision point. Saying which way to go at the junction is the whole of most sets of directions.
1phraseat the junctionWhere two or more roads meet.
“Go right at the junction and the school is on the left.”
at the junction is a phrase.
Practised in Directions & Position