This is the 54th most frequent Russian word.
нас
"Us."
Here, 'нас' is part of a prepositional phrase 'у нас', meaning 'at our place', indicating possession or location.
У нас дома уютно и тепло.
Our house is cozy and warm.
In this example, 'нас' serves as a comparative reference in the accusative case, representing 'us' as compared to 'you'.
Вас больше, чем нас.
There are more of you than us.
Here, 'нас' functions as a pronoun in the accusative case, meaning 'us', indicating the object of the invitation.