This is the 219th most frequent German word.
hinter
"Behind" or "at the back of."
Here, 'hinter' is used as a preposition indicating position or location, meaning 'behind'.
Der Hund ist hinter dem Haus.
The dog is behind the house.
Here, 'hinter' works metaphorically to signify causality or reasoning, 'behind'.
Das Geheimnis liegt hinter den Ereignissen.
The secret lies behind the events.
In this sentence, 'hinter' functions as a preposition to denote a location that provides concealment, 'behind'.