announcer vs caller-out

announcer and caller-out both are nouns.

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

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

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

announcer (noun)	caller-out (noun)
reads news, commercials on radio or television	a person who announces the changes of steps during a dance
someone who proclaims a message publicly