oblateness vs bulginess

oblateness and bulginess both are nouns.

Word	Noun	Adjective	Verb	Adverb
oblateness	Yes	No	No	No
bulginess	Yes	No	No	No

As nouns, bulginess is a hypernym of oblateness; that is, bulginess is a word with a broader meaning than oblateness:

oblateness: the property possessed by a round shape that is flattened at the poles
bulginess: the property possessed by a rounded convexity

Other hypernyms of oblateness include roundedness.

oblateness (noun)	bulginess (noun)
the property possessed by a round shape that is flattened at the poles	the property possessed by a rounded convexity