This is the 18492nd most frequent Russian word.
яму
The Russian word "яму" means "pit" or "hole" in English (accusative case of "яма").
Here, 'яму' is used to denote a specific object, a pit or hole, in the accusative case.
Я увидел яму, когда шёл по дороге.
I saw a pit when I was walking on the road.
In this sentence, 'яму' is part of a prepositional phrase indicating the object of the action in the accusative case.
Он прыгнул через яму, не задерживаясь.
He jumped over the pit without stopping.
Here 'яме' is in the prepositional case, describing a location.