prechlorination vs chlorination

prechlorination and chlorination both are nouns.

Word	Noun	Adjective	Verb	Adverb
prechlorination	Yes	No	No	No
chlorination	Yes	No	No	No

As nouns, chlorination is a hypernym of prechlorination; that is, chlorination is a word with a broader meaning than prechlorination:

prechlorination (noun)	chlorination (noun)
chlorination prior to another chemical process	disinfection of water by the addition of small amounts of chlorine or a chlorine compound
	the addition or substitution of chlorine in organic compounds