eccentricity vs oddity

eccentricity and oddity both are nouns.

Word	Noun	Adjective	Verb	Adverb
eccentricity	Yes	No	No	No
oddity	Yes	No	No	No

As nouns, oddity is a hyponym of eccentricity; that is, oddity is a word with a more specific, narrower meaning than eccentricity:

Other hyponyms of eccentricity include oddness.

eccentricity (noun)	oddity (noun)
strange and unconventional behavior	something unusual -- perhaps worthy of collecting
a circularity that has a different center or deviates from a circular path	a strange attitude or habit
(geometry) a ratio describing the shape of a conic section; the ratio of the distance between the foci to the length of the major axis	eccentricity that is not easily explained