dome vs arena

dome and arena both are nouns.

Word	Noun	Adjective	Verb	Adverb
dome	Yes	No	No	No
arena	Yes	No	No	No

As nouns, arena is a hypernym of dome; that is, arena is a word with a broader meaning than dome:

Other hypernyms of dome include bowl, sports stadium, stadium.

dome (noun)	arena (noun)
a hemispherical roof	a playing field where sports events take place
a stadium that has a roof	a large structure for open-air sports or entertainments
informal terms for a human head	the central area of an ancient Roman amphitheater where contests and spectacles were held; especially an area that was strewn with sand
a concave shape whose distinguishing characteristic is that the concavity faces downward	a particular environment or walk of life