This is the 8622nd most frequent Polish word.
psi
"Psi" in Polish means "dog" (plural adjectival form or related to dogs).
Here, 'psi' refers to dogs and is used as a plural form.
Widzę dwa duże psi.
I see two big dogs.
In this sentence, 'psi' acts as an adjective describing 'age,' meaning 'dog's age'.
Psi wiek bardzo się zmienia depending na rasie.
A dog's age varies significantly depending on the breed.
Here, 'psi' is used as an adjective to describe 'trail,' indicating the trail belongs to a dog.