This is the 170th most frequent Greek word.
ελλάδας
"Ελλάδας" means "of Greece" (possessive form).
Here, 'Ελλάδας' is in the genitive case, denoting possession (of Greece) with respect to 'the history'.
Η ιστορία της Ελλάδας είναι πλούσια και ενδιαφέρουσα.
The history of Greece is rich and interesting.
In this sentence, 'Ελλάδας' is used in the genitive case to describe the map's relation to Greece.
Φωτογράφισα τον χάρτη της Ελλάδας για το πρότζεκτ μου.
I photographed the map of Greece for my project.
The word 'Ελλάδας' in this context is in the genitive case to indicate the connection of the sea to Greece.