southern lights vs aurora

southern lights and aurora both are nouns.

Word	Noun	Adjective	Verb	Adverb
southern lights	Yes	No	No	No
aurora	Yes	No	No	No

As nouns, aurora is a hypernym of southern lights; that is, aurora is a word with a broader meaning than southern lights:

southern lights: the aurora of the Southern Hemisphere
aurora: an atmospheric phenomenon consisting of bands of light caused by charged solar particles following the earth's magnetic lines of force

southern lights (noun)	aurora (noun)
the aurora of the Southern Hemisphere	an atmospheric phenomenon consisting of bands of light caused by charged solar particles following the earth's magnetic lines of force
	the first light of day