This is the 4108th most frequent Polish word.
basenie
"Basenie" means "swimming pool" (locative case) in English.
The word 'basenie' is the locative case of 'basen', meaning 'swimming pool', used after the preposition 'na' to indicate location.
Jestem na basenie od rana.
I have been at the swimming pool since morning.
Here, 'basenie' is in the locative case, used with the preposition 'w' to show the location of the activity of swimming.
Pływamy w basenie codziennie.
We swim in the swimming pool every day.
In this context, 'basenie' is in the locative case, used to indicate proximity to the swimming pool with the preposition 'przy'.