telephone vs hold on

telephone is a noun but hold on is not a noun.

Word	Noun	Adjective	Verb	Adverb
telephone	Yes	No	Yes	No
hold on	No	No	Yes	No

telephone (noun)	hold on (noun)
electronic equipment that converts sound into electrical signals that can be transmitted over distances and then converts received signals back into sounds
transmitting speech at a distance

telephone (verb)	hold on (verb)
get or try to get into communication (with someone) by telephone	be persistent, refuse to stop
	stop and wait, as if awaiting further instructions or developments
	hold the phone line open
	hold firmly
	retain possession of