elliptical vs ellipse

elliptical is not a noun while ellipse is a noun.

Word	Noun	Adjective	Verb	Adverb
elliptical	No	Yes	No	No
ellipse	Yes	No	No	No

elliptical (noun)	ellipse (noun)
	a closed plane curve resulting from the intersection of a circular cone and a plane cutting completely through it

elliptical (adjective)	ellipse (adjective)
characterized by extreme economy of expression or omission of superfluous elements
rounded like an egg