bat boy vs helper

bat boy and helper both are nouns.

Word	Noun	Adjective	Verb	Adverb
bat boy	Yes	No	No	No
helper	Yes	No	No	No

As nouns, helper is a hypernym of bat boy; that is, helper is a word with a broader meaning than bat boy:

bat boy: (baseball) a boy who takes care of bats and other baseball equipment
helper: a person who contributes to the fulfillment of a need or furtherance of an effort or purpose

Other hypernyms of bat boy include assistant, help, supporter, boy, male child.

bat boy (noun)	helper (noun)
(baseball) a boy who takes care of bats and other baseball equipment	a person who helps people or institutions (especially with financial help)
	a person who contributes to the fulfillment of a need or furtherance of an effort or purpose