elongation vs addition

elongation and addition both are nouns.

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

As nouns, addition is a hypernym of elongation; that is, addition is a word with a broader meaning than elongation:

Other hypernyms of elongation include add-on, improver.

elongation (noun)	addition (noun)
the act of lengthening something	the arithmetic operation of summing; calculating the sum of two or more numbers
an addition to the length of something	the act of adding one thing to another
the quality of being elongated	a component that is added to something to improve it
	a suburban area laid out in streets and lots for a future residential area
	something added to what you already have
	a quantity that is added