announcer vs caller

announcer and caller both are nouns.

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

As nouns, caller is a hyponym of announcer; that is, caller is a word with a more specific, narrower meaning than announcer:

Other hyponyms of announcer include caller-out, muadhdhin, muazzin, muezzin, crier, town crier.

announcer (noun)	caller (noun)
reads news, commercials on radio or television	a social or business visitor
someone who proclaims a message publicly	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

announcer (adjective)	caller (adjective)
	providing coolness
	fresh