hold on vs call

hold on is not a noun while call is a noun.

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

hold on (noun)	call (noun)
	(sports) the decision made by an umpire or referee
	a visit in an official or professional capacity
	a brief social visit
	the option to buy a given stock (or stock index or commodity future) at a given price before a given date
	a method of contacting a person by phone
	a loud utterance; often in protest or opposition
	the characteristic sound produced by a bird
	a request
	a demand
	a demand for a show of hands in a card game
	an instruction that interrupts the program being executed
	a demand by a broker that a customer deposit enough to bring his margin up to the minimum requirement

hold on (verb)	call (verb)
be persistent, refuse to stop	rouse somebody from sleep with a call
stop and wait, as if awaiting further instructions or developments	challenge the sincerity or truthfulness of
hold the phone line open	consider or regard as being
hold firmly	utter in a loud voice or announce
retain possession of	ascribe a quality to or give a name of a common noun that reflects a quality
	get or try to get into communication (with someone) by telephone
	assign a specified (usually proper) name to
	utter a characteristic note or cry
	send a message or attempt to reach someone by radio, phone, etc.; make a signal to in order to transmit a message
	order, request, or command to come
	indicate a decision in regard to
	challenge (somebody) to make good on a statement; charge with or censure for an offense
	declare in the capacity of an umpire or referee
	utter a sudden loud cry
	make a prediction about; tell in advance
	lure by imitating the characteristic call of an animal
	present for redemption before maturation
	read aloud to check for omissions or absentees
	order, summon, or request for a specific duty or activity, work, role
	order or request or give a command for
	give the calls (to the dancers) for a square dance
	make a demand, as for a card or a suit or a show of hands
	demand payment of (a loan)
	pay a brief visit
	call a meeting; invite or command to meet
	make a stop in a harbour
	greet, as with a prescribed form, title, or name
	stop or postpone because of adverse conditions, such as bad weather