This is the 214th most frequent Russian word.
дом
House; home.
In this sentence, 'дом' is used to denote a physical building used as a residence.
Я живу в доме.
I live in the house.
Here, 'дом' is transformed into 'дома' to specify a non-location-specific state of being 'at home'.
Вечером я буду дома.
I will be at home in the evening.
In this example, 'дом' refers to a particular structure that serves as a residential building.