fireman vs pitcher

fireman and pitcher both are nouns.

Word	Noun	Adjective	Verb	Adverb
fireman	Yes	No	No	No
pitcher	Yes	No	No	No

As nouns, pitcher is a hypernym of fireman; that is, pitcher is a word with a broader meaning than fireman:

Other hypernyms of fireman include hurler, twirler.

fireman (noun)	pitcher (noun)
play in which children pretend to put out a fire	the position on a baseball team of the player who throws the ball for a batter to try to hit
a member of a fire department who tries to extinguish fires	an open vessel with a handle and a spout for pouring
a laborer who tends fires (as on a coal-fired train or steamship)	(baseball) the person who does the pitching
a pitcher who does not start the game	(botany) a leaf that is modified in such a way as to resemble a pitcher or ewer
	the quantity contained in a pitcher