doorman vs ticket taker

doorman and ticket taker both are nouns.

Word	Noun	Adjective	Verb	Adverb
doorman	Yes	No	No	No
ticket taker	Yes	No	No	No

As nouns, ticket taker is a hyponym of doorman; that is, ticket taker is a word with a more specific, narrower meaning than doorman:

doorman: someone who guards an entrance
ticket taker: someone who is paid to admit only those who have purchased tickets

Other hyponyms of doorman include commissionaire, night porter, ticket collector.

doorman (noun)	ticket taker (noun)
someone who guards an entrance	someone who is paid to admit only those who have purchased tickets