improver vs elongation

improver and elongation both are nouns.

Word	Noun	Adjective	Verb	Adverb
improver	Yes	No	No	No
elongation	Yes	No	No	No

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

Other hyponyms of improver include additive, afterthought, annex, annexe, extension, wing, attachment, extension.

improver (noun)	elongation (noun)
a component that is added to something to improve it	the act of lengthening something
someone devoted to the promotion of human welfare and to social reforms	an addition to the length of something
	the quality of being elongated