Isthmus of Panama vs Isthmus of Darien

Isthmus of Panama and Isthmus of Darien both are nouns.

Word	Noun	Adjective	Verb	Adverb
Isthmus of Panama	Yes	No	No	No
Isthmus of Darien	Yes	No	No	No

As nouns, Isthmus of Panama and Isthmus of Darien are synonyms defined as:

Isthmus of Panama and Isthmus of Darien: the isthmus that connects Central America and South America; was formerly called the Isthmus of Darien

Isthmus of Panama (noun)	Isthmus of Darien (noun)
the isthmus that connects Central America and South America; was formerly called the Isthmus of Darien	the isthmus that connects Central America and South America; was formerly called the Isthmus of Darien