This is the 487th most frequent Greek word.
γιάννη
"Γιάννη" is the vocative form of "Γιάννης," the Greek equivalent of the name "John."
Here, 'Γιάννης' is used as a proper noun referring to a person's name in the nominative case.
Ο Γιάννης πηγαίνει στο πάρκο.
John is going to the park.
In this sentence, 'τον Γιάννη' refers to the name in the accusative case, as it is the direct object of the verb.
Είδα τον Γιάννη στο σχολείο.
I saw John at the school.
Here, 'του Γιάννη' indicates possession in the genitive case, showing ownership of the café.