Peloponnesian Peninsula vs Peloponnese

Peloponnesian Peninsula and Peloponnese both are nouns.

Word	Noun	Adjective	Verb	Adverb
Peloponnesian Peninsula	Yes	No	No	No
Peloponnese	Yes	No	No	No

As nouns, Peloponnesian Peninsula and Peloponnese are synonyms defined as:

Peloponnesian Peninsula and Peloponnese: the southern peninsula of Greece; dominated by Sparta until the 4th century BC

Other synonyms of Peloponnesian Peninsula include Peloponnesus.

Peloponnesian Peninsula (noun)	Peloponnese (noun)
the southern peninsula of Greece; dominated by Sparta until the 4th century BC	the southern peninsula of Greece; dominated by Sparta until the 4th century BC