cooling tower vs cooling

cooling tower and cooling both are nouns.

Word	Noun	Adjective	Verb	Adverb
cooling tower	Yes	No	No	No
cooling	Yes	No	No	No

As nouns, cooling is a hypernym of cooling tower; that is, cooling is a word with a broader meaning than cooling tower:

cooling tower: a cooling system used in industry to cool hot water (by partial evaporation) before reusing it as a coolant
cooling: a mechanism for keeping something cool

Other hypernyms of cooling tower include cooling system.

cooling tower (noun)	cooling (noun)
a cooling system used in industry to cool hot water (by partial evaporation) before reusing it as a coolant	a mechanism for keeping something cool
	the process of becoming cooler; a falling temperature