batman vs attender

batman and attender both are nouns.

Word	Noun	Adjective	Verb	Adverb
batman	Yes	No	No	No
attender	Yes	No	No	No

As nouns, attender is a hypernym of batman; that is, attender is a word with a broader meaning than batman:

batman: an orderly assigned to serve a British military officer
attender: someone who waits on or tends to or attends to the needs of another

Other hypernyms of batman include attendant, tender.

batman (noun)	attender (noun)
an orderly assigned to serve a British military officer	someone who waits on or tends to or attends to the needs of another
	a person who is present and participates in a meeting
	someone who listens attentively