convener vs caller

convener and caller both are nouns.

Word	Noun	Adjective	Verb	Adverb
convener	Yes	No	No	No
caller	Yes	Yes	No	No

As nouns, caller is a hypernym of convener; that is, caller is a word with a broader meaning than convener:

convener (noun)	caller (noun)
the member of a group whose duty it is to convene meetings	a social or business visitor
	the person initiating a telephone call
	the person who convenes a meeting
	someone who proclaims or summons in a loud voice
	a person who announces the changes of steps during a dance
	the bettor in a card game who matches the bet and calls for a show of hands
	an investor who buys a call option

convener (adjective)	caller (adjective)
	providing coolness
	fresh