mirage vs fata morgana

mirage and fata morgana both are nouns.

Word	Noun	Adjective	Verb	Adverb
mirage	Yes	No	No	No
fata morgana	Yes	No	No	No

As nouns, fata morgana is a hyponym of mirage; that is, fata morgana is a word with a more specific, narrower meaning than mirage:

mirage: an optical illusion in which atmospheric refraction by a layer of hot air distorts or inverts reflections of distant objects
fata morgana: a mirage in the Strait of Messina (attributed to the Arthurian sorcerer Morgan le Fay)

mirage (noun)	fata morgana (noun)
something illusory and unattainable	a mirage in the Strait of Messina (attributed to the Arthurian sorcerer Morgan le Fay)
an optical illusion in which atmospheric refraction by a layer of hot air distorts or inverts reflections of distant objects