A word used to indicate relationships between different elements in a sentence, such as location, direction, time, or cause.
In German, prepositions can govern different cases (accusative, dative, or genitive).
Examples
Accusative preposition:
Ich gehe durch den Park.
I walk through the park.
Dative preposition:
Wir treffen uns nach der Schule.
We meet after school.
Genitive preposition:
Trotz des Regens gehen wir spazieren.
Despite the rain, we are going for a walk.