fermata vs prolongation

fermata and prolongation both are nouns.

Word	Noun	Adjective	Verb	Adverb
fermata	Yes	No	No	No
prolongation	Yes	No	No	No

As nouns, prolongation is a hypernym of fermata; that is, prolongation is a word with a broader meaning than fermata:

fermata: (music) a prolongation of unspecified length on a note or chord or rest
prolongation: the consequence of being lengthened in duration

Other hypernyms of fermata include continuation, lengthiness, protraction.

fermata (noun)	prolongation (noun)
(music) a prolongation of unspecified length on a note or chord or rest	the act of prolonging something
a musical notation (over a note or chord or rest) that indicates it is to be prolonged by an unspecified amount	amount or degree or range to which something extends
	the consequence of being lengthened in duration