rental vs holding

rental and holding both are nouns.

Word	Noun	Adjective	Verb	Adverb
rental	Yes	Yes	No	No
holding	Yes	No	No	No

As nouns, holding is a hypernym of rental; that is, holding is a word with a broader meaning than rental:

rental: property that is leased or rented out or let
holding: something owned; any tangible or intangible possession that is owned by someone

Other hypernyms of rental include belongings, property.

rental (noun)	holding (noun)
the act of paying for the use of something (as an apartment or house or car)	the act of retaining something
property that is leased or rented out or let	something owned; any tangible or intangible possession that is owned by someone

rental (adjective)	holding (adjective)
of or relating to rent
available to rent or lease